NCERT Solutions for Class 9

From the following table, students can find out the NCERT Solutions for Class 9 Science, Hindi, Maths, and English. Students who are preparing for the exams like Olympiad, NTSE must have a strong foundation over the NCERT Solutions for Class 9. As most of the questions in these exams are derived from the NCERT curriculum so in order to crack these exams students must have a strong command over NCERT Solutions for Class 9.

NCERT Solutions For Class 9 Science Chapter 15 Improvement in Food Resources

NCERT Solutions Class 9 Science Chapter 15 Improvement in Food Resources – Here are all the NCERT solutions for Class 9 Science Chapter 15. This solution contains questions, answers, images, step by step explanations of the complete Chapter 15 titled Improvement in Food Resources of Science taught in class 9. If you are a student of class 9 who is using NCERT Textbook to study Science, then you must come across Chapter 15 Improvement in Food Resources. After you have studied lesson, you must be looking for answers of its questions. Here you can get complete NCERT Solutions for Class 9 Science Chapter 15 Improvement in Food Resources in one place. For a better understanding of this chapter, you should also see Chapter 15 Improvement in Food Resources Class 9 notes , Science.

Topics and Sub Topics in Class 9 Science Chapter 15 Improvement in Food Resources:

  1. Improvement in Food Resources
  2. Improvement in Crop Yields
  3. Animal Husbandry

These solutions are part of NCERT Solutions for Class 9 Science. Here we have given Class 9 NCERT Science Text book Solutions for Chapter 15 Improvement in Food Resources.

In-Text Questions Solved

NCERT Textbook for Class 9 Science – Page 204
Question 1. What do we get from cereals, pulses, fruits and vegetables?
Answer: Cereals give carbohydrates which provide energy.
Pulses give proteins which build our body.
Vegetables and fruits provide vitamins and minerals.

More Resources for CBSE Class 9

Class 9 Science NCERT Textbook – Page 205
Question 1. How do biotic and abiotic factors affect crop production?
Answer: Factors responsible for loss of grains, during storage and production are:
(a) Biotic factors like rodents, pests, insects, etc.
(b) Abiotic factors like temperature, humidity, moisture, etc.
Combination of both biotic and abiotic factors causes :

  1. infestation of insects
  2. weight loss
  3. poor germination ability
  4. degradation in quality
  5. discolouration
  6. poor market price

Question 2. What are the desirable agronomic characteristics for crop improvements?
Answer: Desirable agronomic characteristics for crop improvements are:
(a) Tallness and profuse branching are desirable characters for fodder crops.
(b) Dwarfness is desired in cereals, so that less nutrients are consumed by these crops.

Formulae Handbook for Class 9 Maths and ScienceEducational Loans in India

NCERT Textbook for Class 9 Science – Page 206
Question 1. What are macro-nutrients and why are they called macro-nutrients?
Answer: Macro-nutrients are the essential elements which are utilised by plants in large quantities. Many macro-nutrients are required by the plants for the following functions:

  • As the constituent of protoplasm
  • N, P, S are present in proteins
  • Ca is present in cell wall
  • Mg is important constituent of chlorophyll

Question 2. How do plants get nutrients?
Answer: Plants get nutrients from air, water and soil. There are, sixteen nutrients essential for the growth of plants. Carbon and Oxygen are supplied by water. The remaining thirteen nutrients are supplied by soil.

Class 9 Science NCERT Textbook – Page 207
Question 1. Compare the use of manure and fertilizers in maintaining soil fertility.
Answer: Effects of using manures on soil quality:

  1. The manures enrich the soil with nutrients.
  2. They provide a lot of organic matter (humus) to the soil and thus restores water retention capacity of sandy soils and drainage in clayey soil.
  3. The addition of manures reduces soil erosion.
  4.  They provide food for soil organisms, like soil friendly bacteria.

Effects of using fertilizers on soil quality:

  1. By the continuous use of fertilizers, the soil becomes powdery, dry and rate of soil erosion increases.
  2. By the use of fertilizers, the organic matter decreases which further decreases the porosity of soil and the plant roots do not get oxygen properly,
  3. The nature of soil changes to acidic or basic.

NCERT Textbook for Class 9 Science – Page 208
Question 1. Which of the following conditions will give the most benefits? Why?
(a) Farmers use high-quality seeds, do not adopt irrigation or use fertilizers.
(b) Farmers use ordinary seeds, adopt irrigation and use fertilizer.
(c) Farmers use quality seeds, adopt irrigation, use fertilizer and use crop protection measures.
Answer: In this, (c) Farmers use quality seeds, adopt irrigation, use fertilizer and use crop protection measures.
Use of any quality seeds is not sufficient until they are properly irrigated, enriched with fertilizers and protected from biotic factors. Hence, option (c) will give the most benefits.

Class 9 Science NCERT Textbook – Page 209
Question.1. Why should preventive measures and biological control methods be preferred for protecting crops?
Answer. Diseases in plants are caused by pathogens. To get rid of pathogens, some preventive measures and biological control methods are used as they are simple, economic and minimise pollution without affecting the soil quality.

Question 2. What factors may be responsible for losses of grains during storage?
Answer: The factors responsible for losses of grains during storage are:

  • Abiotic factors like moisture (present in food grains), humidity (of air) and temperature.
  • Biotic factors like insects, rodents, birds, mites, bacteria and fungi.

NCERT Textbook for Class 9 Science – Page 210
Question 1. Which method is commonly used for improving cattle breeds and why ?
Answer: Cross breeding is a process in which indigenous varities of cattle are crossed by exotic breeds to get a breed which is high yielding. During cross breeding, the desired characters are taken into consideration. The offspring should be high yielding, should have early maturity and should be resistant to climatic conditions.

Class 9 Science NCERT Textbook – Page 211
Question 1. Discuss the implications of the following statement:
“It is interesting to note that poultry is India’s most efficient converter of low fibre food stuff (which is unfit for human consumption) into highly nutritious animal protein food”.
Answer: The basic aim of poultry farming is to raise domestic fowl for egg production and chicken meat. These poultry birds are not only the efficient converters of agricultural by-products, particularly cheaper fibrous wastes (which is unfit for human consumption but can be formulated into cheaper diets for poultry birds) into high quality meat and also help in providing egg, feathers and nutrient rich manure. For this reasons, it is said that, “poultry is India’s most efficient converter of low fibre food stuff into highly nutritious animal protein food”.

NCERT Textbook for Class 9 Science – Page 211
Question 1. What management practices are common in dairy and poultry farming?
Answer:

  1. Shelter: Dairy animals and poultry birds require proper shelter, i.e., well designed dairy and hygienic shelter.
  2. Feeding: To get good yield of food product, proper feed is provided to dairy animals and poultry birds.
  3. Caring for animal health: Animal and birds must be protected from diseases caused by virus, bacteria or fungi.

Question 2. What are the differences between broilers and layers and in their management?
Answer: The poultry bird groomed for obtaining meat is called broiler. The egg laying poultry bird is called layer.
The housing, nutritional and environmental requirements of broilers are somewhat different from those of egg layers.
The ration (daily food requirement) for broilers is protein rich with adequate fat. The level of vitamins A and K is kept high in the poultry feeds while layers require enough space and proper lightning.

Class 9 Science NCERT Textbook – Page 213
Question 1. How are fish obtained?
Answer: There are two ways of obtaining fish. One is from natural resources, which is called capture fishing. The other way is by fish farming, which is called culture fishery.

Question 2. What are the advantages of composite fish culture?
Answer:  In composite fish culture, a combination of five or six fish species is used in a single fish pond. These species are selected so that they do not compete for food among them and are having different types of food habits. As a result, the food available in all the parts of the pond is used. For example, Catlas are surface feeders, Rohus feed in the middle-zone of the pond, Mrigals and Common Carps are bottom feeders and Grass Carps feed on the weeds, together these species can use all the food in the pond without competing with each other. This increases the fish yield from pond.

NCERT Textbook for Class 9 Science – Page 213
Question 1. What are the desirable characters of bee varieties suitable for honey production?
Answer:

  1. The variety of bee should be able to collect a large amount of honey.
  2.  The bees should stay in a given beehive for a longer period.
  3. The bees should have capacity of breeding well.
  4. The variety of bee should be disease resistant.

Question 2. What is pasturage and how is it related to honey production?
Answer: The pasturage means the flowers available to the bees for nectar and pollen collection. In addition to adequate quantities of pasturage, the kind of flowers available will determine the taste of the honey.

Questions From NCERT Textbook for Class 9 Science

Question 1. Explain any one method of crop production which ensures high yield.
Answer:  One method used for crop production which ensures high yield is plant breeding. It is the science involved in improving the varieties of crops by breeding plants. The plants from different areas/places is picked up with desired traits and then hybridisation or cross-breeding of these varieties is done to obtain a plant/crop of desired characteristic.
The high yielding crop variety shows the following characteristics:
High yield, early maturation, less water for irrigation, better quality seeds are produced, less fertilizers required, adapts itself to the environmental conditions.

Question 2. Why are manure and fertilizers used in fields?
Answer: They are used to ensure good vegetative growth (leaves, branches and flowers), giving rise to healthy plants, that results in high crop production.

Question 3. What are the advantages of inter-cropping and crop rotation?
Answer:  Advantages of using inter-cropping:

  1. It helps to maintain soil fertility.
  2. It increases productivity per unit area.
  3. Save labour and time.
  4. Both crops can be easily harvested and processed separately.

Advantages of using crop rotation:

  1. It improves the soil fertility.
  2. It avoids depletion of a particular nutrient from soil.
  3. It minimise pest infestation and diseases.
  4. It helps in weed control.
  5. It prevents change in the chemical nature of the soil.

Question 4. What is genetic manipulation? How is it useful in agricultural practices?
Answer: Genetic manipulation is a process of incorporating desirable (genes) characters into crop varieties by hybridisation. Hybridisation involves crossing between genetically dissimilar plants. This is done for production of varieties with desirable characteristics like profuse branching in fodder crops, high yielding varieties in maize, wheat, etc.
Genetic manipulation is useful in developing varieties which shows:

  • Increased yield
  • Better quality
  • Shorter and early maturity period
  • Better adaptability to adverse environmental conditions
  • Desirable characteristics

Question 5. How do storage grain losses occur?
Answer: The factors responsible for loss of grains during storage are:

  1. Abiotic factors like moisture (present in foodgrains), humidity (of air) and temperature.
  2. Biotic factors like insects, rodents, birds, mites and bacteria.

Question 6. How do good animal husbandry practices benefit farmers?
Answer: Good animal husbandry practices are beneficial to the farmers in the following ways:

  1. Improvement of breeds of the domesticated animals.
  2. Increasing the yield of foodstuffs such as milk, eggs and meat.
  3. Proper management of domestic animals in terms of shelter, feeding, care and protection against diseases.
    Which ultimately helps the farmers to improve their economic condition.

Question 7. What are the benefits of cattle farming?
Answer:  Cattle farming is beneficial in the following ways:

  1. Milk production is increased by high yielding animals.
  2. Good quality of meat, fibre and skin can be obtained.
  3. Good breed of draught animals can be obtained.

Question 8.  For increasing production, what is common in poultry, fisheries and bee-keeping?
Answer: Through cross breeding, the production of poultry, fisheries and bee-keeping can be increased.

Question 9.  How do you differentiate between capture fishing, mariculture, and aquaculture?
Answer:
Capture fishing: It is the fishing in which fishes are captured from natural resources like pond, sea water and estuaries.
Mariculture: It is the culture of fish in marine water. Varieties like prawns, oysters, bhetki and mullets are cultured for fishing.
Aquaculture: It is done both in fresh water and in marine water.

NCERT Solutions for Class 9 Science Chapter 15 Improvement in Food Resources (Hindi Medium)

9 Science Chapter 15 Improvement in Food Resources Intext Questions on Page 229
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9 Science Chapter 15 Improvement in Food Resources Intext Questions on Page 235 in pdf
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NCERT Sols for Class 9 Science Chapter 15 Improvement in Food Resources अभ्यास के प्रश्न उत्तर
NCERT Sols for Class 9 Science Chapter 15 Improvement in Food Resources अभ्यास के प्रश्न उत्तर in pdf form
NCERT Sols for Class 9 Science Chapter 15 Improvement in Food Resources अभ्यास के प्रश्न उत्तर for up, mp, gujrat board
NCERT Solutions for Class 9 Science Chapter 15 Improvement in Food Resources in pdf

More Questions Solved 

NCERT Solutions For Class 9 Science Chapter 15 Multiple Choice Questions

Choose the correct option:

1.  The use of fertilizers in farming is an example of
(a) No cost production (b) Low-cost production
(c) High-cost production (d) None of these

2.  Nitrogen, phosphorus, potassium are examples of
(a) micro-nutrients (b) macro-nutrients
(c) fertilizer (d) both (ct) and (b)

3.  Xanthium, Parthenium, Cyperinus are the examples of
(a) diseases (b) pesticides
(c) weeds (d) pathogens

4. Mullets, bhetki, pearl spots, prawns, mussels are the example of
(a) marine fishes (b) fresh-water fishes
(c) finned fishes (d) shell fish

5.  Apis cerana indica is commonly known as
(a) Indian cow (b) Indian buffalo
(c) Indian bee (d) None of these

6. The production and management of fish is called
(a)pisciculture (b) apiculture
(c) sericulture(d) aquaculture

7. Catla and Rohu are examples of
(a) freshwater fish (b) marine water fish
(c) both (a) and (b)(d) none of these

8. Pasturage is related to
(a) cattle (b) fishery
(c) apiculture (d) poultry

9. Growing two oronore crops in definite patterns is known as
(a) crop rotation (b) inter-cropping
(d) organic cropping(c) mixed cropping

10. Leghorn and Aseel are related to
(a) apiculture (b) dairy farming
(c) pisciculture (d) poultry

Answer:  1—(c), 2—(b), 3—(c), 4—(a), 5—(c), 6-(a), 7-(a), 8—(c), 9—(b), 10—(d).

NCERT Solutions For Class 9 Science Chapter 15 Very Short Answer Type Questions

Question 1. Name any two fodder crops.
Answer:  Berseem, oats or sudan grass are raised as food for the livestock, called fodder crops.

Question 2. What do you understand b.y photoperiod of sunlight?
Answer: Photoperiod are related to the duration of sunlight required for plant growth.

Question 3. Name two kharif crops.
Answer: Paddy and soyabean.

Question 4. Name two rabi crops.
Answer:  Wheat and gram.

Question 5. Define hybridisation.
Answer: Hybridisation refers to crossing between genetically dissimilar plants, to obtain, better variety of crops.

Question 6. What are genetically modified crops?
Answer: By introducing a gene with required characters into a crop for its improvement is called genetically modified crop.

Question 7. “Shorter the duration of the crop from sowing to harvesting, the more economical is the variety”. Give reason for this.
Answer: Due to short duration of crop growth, farmers can grow more crops in a year, and reduce the cost of drop production.

Question 8. Name different types of crop production practices involved in India.
Answer: They are (a) no cost production, (b) low cost production and (c) high cost production.

Question 9. Who provides nutrients to plants?
Answer: Nutrients to plants are provided by air, water and soil.

Question 10. What are macro-nutrients?
Answer: The nutrients required by plants in larger quantity is called macro-nutrients. They are nitrogen, phosphorus, potassium, calcium, magnesium and sulphur.

Question 11. Name the nutrients that plant obtain from air and water.
Answer: Air – Carbon and oxygen Water- Hydrogen and oxygen

Question 12. State the difference between compost and vermi-compost.
Answer: The compost is obtained by decomposition of organic waste like animal excreta, plant waste etc. naturally due to decomposition by bacteria.
Vermi-compost: To hasten the process of decomposition redworms are added to this organic matter to obtain compost.

Question 13. Name any two weeds.
Answer: Parthenium and Xanthium.

Question 14. What causes disease in plants?
Answer:  It is caused by pathogens such as bacteria, fungi and viruses.

Question 15. Name two Indian cattle.
Answer: Bos indicus – cows 4 Bos bubalis – buffaloes

Question 16.  Name two exotic breeds of cattle.
Answer: Jersey and Brown Swiss

Question 17. Name two variety of food required for milch animals.
Answer:

  • Maintenance requirement – food required to keep animal healthy
  • Milk producing requirement – food required for increased lactation Animal food includes roughage and concentrate also.

Question 18.  State the meaning of capture fishing and culture fishing.
Answer: Capture fishing: It is done from natural resources.
Culture fishing: It is done by fish farming.

Question 19. Name four marine fish varieties.
Answer: Pomphret, mackerel, tuna and sardines.

Question 20. What is apiculture?
Answer: Keeping bee for obtaining honey commercially is called apiculture.

Question 21. Name the products obtained from apiculture.
Answer: Honey and wax both are obtained from apiculture.

NCERT Solutions For Class 9 Science Chapter 15 Short Answer Type Questions

Question 1. What are the major group of activities involved for improvement of crop yields?
Answer:

  • Crop variety improvement
  • Crop production improvement
  • Crop protection improvement

Question 2. What are the different ways/ methods of hybridisation?
Answer:  Hybridisation can be

  • Intervarietal – between different varieties of crops
  • Interspecific – between two species of same genus
  • Intergeneric – between two different genera

Question 3. What are the main characters required in a crop during its improvement practices?
Answer: The useful characters that are required in a crop during its improvement:
(a) Disease resistance (b) Response to fertilizer
(c) Product quality and (d) High yield.

Question 4. State the difference between macro-nutrients and micro-nutrients.
Answer:
NCERT Solutions For Class 9 Science Chapter 15 Improvement in Food Resources SAQ Q4

Question 5. How do deficiency of nutrients affect the crop?
Answer: Deficiency of any nutrient affects physiological processes in plants including reproduction, growth and susceptibility to diseases.

Question 6. State the difference between manure and fertilizer.
Answer:
NCERT Solutions For Class 9 Science Chapter 15 Improvement in Food Resources SAQ Q6

Question 7. What are the harmful effects of fertilizer? .
Answer. It causes soil and water pollution. Continuous use can also destroy soil fertility.

Question 8. What is organic farming?
Answer: It is the farming in which no chemical fertilizers, pesticides or herbicides are used. But uses all organic matter for its growth like manure, neem leaves as pesticides and for grain storage.

Question 9. State the preventive and control measures used before grains are stored.
Answer:

  • Cleaning of the grains
  • Proper drying of the produce in sunlight, there should be no moisture.
  • Fumigation of produce using chemicals that kills pest.

Question 10. Name few varieties of bees used for commercial honey production.
Answer:
Apis cerana indica – Indian bee
A. dorsata – rock bee (local varieties)
A. florae – the little bee
A. mellifera – Italian bee variety

Question 11. What decide the quantity and quality of honey production in apiary?
Answer: For quality of honey: The pasturage, f.e., the kind of flowers available to the bees for nectar and pollen collection will determine the taste of the honey. For quantity of honey: Variety of bee used for the collection of honey. For example, A. mellifera is used to increase yield of honey.

Question 12. How are crops useful to us? What do they provide?
Answer: Crops provide us food for our daily body nutrient. Carbohydrate for energy
requirement – Cereals such as wheat, rice, maize.
Protein for body building — Pulses like gram, lentil
Fats for energy — Oil seed like mustard, sunflower
Vitamins and minerals — From vegetables, spices and fruits
Fodder crops — For livestocks

Question 13. What are the factors for which variety improvement of crop is done?
Answer:
(a) Higher yield: It increases production of crop.
(b) Biotic and abiotic resistance: Crop should be resistant to biotic factors
like diseases, insects, pests and abiotic factor like drought, salinity, heat, cold, frost and water logging.
(c) Change in maturity duration: Short-duration maturity allows farmer to grow more crops in a year and reduces the cost of crop production.
(d) Wider adaptability: Crop’should be able to adapt to changing environmental conditions.
(e) Desirable agronomic characteristics: The tallness and dwarfness of crop. Dwarfness is required for cereals, so that less nutrients are consumed.

Question 14. Name the sources and the nutrients supplied by them to the plants.
Answer:
NCERT Solutions For Class 9 Science Chapter 15 Improvement in Food Resources SAQ Q14

Question 15. What are manures? Give its classification.
Answer: Manures contain large ‘ quantities of organic matter and supplies small quantities of nutrients to the soil. It is prepared naturally by the decomposition of animal waste, excreta and plant waste.

  • It helps in the soil enrichment with nutrients.
  • It helps in improving the soil structure.
  • It helps in increasing the water holding capacity in sandy soils.
  • In clayey soils it helps in the water drainage and prevent water logging. Manure is classified based on the kind of biological material used to make it as : (i) Compost (ii) Vermi-compost (iitj Green manure
    (i) Compost: The farm waste and livestock excreta, along with vegetable waste, sewage waste, weeds, straws etc. are allowed to decompose in a pit is called compost. The compost is rich in nutrients.
    (ii) Vermi-compost: When the above given matter is allowed to decompose in the pit along with some earthworms, the decomposition speeds up and is called vermi-composting.
    (iii) Green manure: Some plants like sun-hemp or guar are grown and then mulched by ploughing them into the soil. This is done before the sowing of crop seeds into the field.
    These green plants present in the soil acts as green manure which enriches the soil in nitrogen and phosphorus.

Question 16. What are fertilizers? Excess use of fertilizers is not advisable, explain?
Answer: Fertilizers are obtained artificially on commercial basis. It is a chemical which contains the nutrients required for the crop to grow. Fertilizers supply various nutrients as they are nutrient specific e.g.-urea provides nitrogen. Mixed fertilizer provides any two mixture of nutrients. They are expensive but their use yield large production hence are a factor of high cost farming.
Excessive use of fertilizers are not advisable as:
(a) It leads to soil and water pollution.
(b) It can destroy the fertility of soil. As the soil is not replenished, micro¬organisms in the soil are harmed by fertilizers.

Question 17. What are the different patterns of cropping?
Or
What are the different cropping systems?
Answer:  Different ways/patterns / systems of growing crop’s are:
(a) Mixed cropping (b) Inter-cropping (c) Crop rotation.
Mixed cropping: It is a method in which two or more crops grow simultaneously on the same piece of land.
Example, Wheat + grain, wheat + mustard or groundnut + sunflower.
This helps in the reduction of risk factor and provides insurance against failure of one of the crops.
Inter-cropping: It is a method of growing two or more crops simultaneously on the same field in a definite patterns. A few row of one crop alternate with a few rows of second crop.
Example, soyabean + maize or bajra + lobia
Crop rotation: The growing of different crops on a piece of land in a pre¬planned succession is known as crop rotation.
The availability of moisture and irrigation facility decides the choice of crop to be cultivated after one harvest.

Question 18.  How does insect pests attack the plant and affect it?
Answer: Insect pests attack the plants in three ways:

  1. They cut the root, stem and leaf.
  2. They suck the cell sap from various parts of the plant.
  3. They bore into stem and fruits.

This way they affect the health of the crop and reduces yield.

Question 19. Give different methods of weed control.
Answer: Weeds can be controlled by different methods:
(a) Weedicides: These are the chemicals sprayed on the weeds to kill them. Excessive use is poisonous and causes environmental pollution.
(b) Mechanical removal: In this method weeds are uprooted by removing manually or by machines.
(c) Preventive methods: Proper seed bed preparation, timely sowing of crops, intercropping and crop rotation helps in weed control.

Question 20. What are the new variety/traits obtained by cross breeding of Indian and exotic breeds of poultry?
Answer: The new variety/traits obtained by cross breeding of Indian and exotic breeds of poultry are:

  1. Number and quality of chicks
  2. Dwarf broiler parent for commercial chick production
  3. Summer adaptation capacity/tolerance to high temperature
  4. Low maintenance requirements
  5. Reduction in the size of the egg-laying bird with ability to utilise more fibrous and cheaper diet, formulated using agricultural by-products

Question 21. State the difference between egg-layers and broiler.
Answer:
NCERT Solutions For Class 9 Science Chapter 15 Improvement in Food Resources SAQ Q21

NCERT Solutions For Class 9 Science Chapter 15 Long Answer Type Questions

Question 1. What are the various methods of irrigation in India?
Answer: Most of agriculture in India is rain-fed, several different kinds of irrigation system are adopted to supply water to agricultural lands. The resources are- wells, canals, rivers and tanks.

  • Wells: Dug wells and tube wells. In dug wells water is collected from water— bearing strata.
  • Tubewells: Can tap water from deeper strata.
  • Canals: Most extensive irrigation system. Canals receive water from reservoirs or rivers. The main canal is divided into branch canals having further distributaries to irrigate fields.
  • River lift system: Water is directly drawn from the river for supplementing irrigation in areas close to rivers.
  • Tanks: These are small storage reservoirs, which intercept and store the run-off of smaller catchment areas.

Question 2. Large amount of food grains get spoiled every year in India due to improper storage of food grains. How can this be avoided?
Answer: Food grains get spoiled by insects, fungi, rodents, bacteria, moisture, temperature in the place of storage.
Storage losses can be minimised by following preventive and control measures.

  1. The seeds/grains that are to be stored should be dry, with no moisture in it.
  2. The grains should be cleaned.
  3. The grains should be fumigated using chemicals that kills pest.
  4. The storage houses should be water proof.
  5. The grains should be stored in sealed gunny bags or metal containers,
  6. The bags should be stacked in order i.e. in pile for proper fumigation, and should be kept few centimetres away from the wall.
  7. The ventilators if any should be closed tightly, to avoid birds visiting the storage house and destroying the grains.
  8. The walls and the floor should be water-proof with no holes in it, to avoid rodents, pests.

Question 3. Explain different types of fisheries.
Answer: The different types of fisheries are marine fisheries, inland fisheries, capture fishing, mariculture and aquaculture.

  • Marine fisheries: Marine fishes are caught using fishing nets. Large schools of fishes is located by satellites. Some are farmed in sea water.
  • Mariculture: Marine fishes are cultured in seawater this culture of fisheries is called mariculture.
  • Inland fisheries: The fisheries done in fresh water resources like canals, ponds, reservoirs and rivers is called inland fisheries.
  • Capture fishing: It is done in sea-water, estuaries and lagoons.
  • Aquaculture: Culture of fish done in different water bodies is called aquaculture.

Question 4. What are the practices used for dairy industry?
Answer: The practices required for raising daily animals to get the optimum yield are:
(i) Shelter, (ii) feeding, (iii) rearing of animals, (iv) breeding.
(i) Shelter: The shelter should be clean, spacious and airy.
(ii) Feeding: Proper food is essential for dairy animals, two types of food are roughage and concentrates. Proper feed at proper time is required for dairy animals.
(iii) Rearing of animals: Providing them proper health care and protection from pathogens, diseases and proper vaccination.
(iv) Breeding: The crossing of different variety of milch animals to obtain a breed that can produce more yield of milk.

NCERT Solutions For Class 9 Science Chapter 15 Value-Based Questions

Question 1. A group of Eco Club students made a compost pit in the school, they collected all bio-degradable waste from the school canteen and used it to prepare the compost.
(a) Name two waste that can be used for the compost and two wastes obtained from canteen which cannot be used for the compost making?
(b) What is the other important component required for making the compost?
(c) What values of Eco Club students are reflected in this act?
Answer:
(a) Two waste used for compost are vegetable peels and fruit peels. Two waste material that cannot be used as compost are polythene bags and plastic items.
(b) Bacteria and fungi present in soil are the other important component for making compost.
(c) Eco Club students reflect the value of group work, responsible citizens.

Question 2. Surjeet read an article in the newspaper that prolonged and excess use of pesticides and fertilizers leads to cancer in human beings. He also saw the increased number of cancer patients in his town. He started educating the farmers in his town to minimize or stop the use of chemicals in farming and adopt the organic farming.
(a) What is the most common pesticide used in our country?
(b) Give one difference in organic farming and chemical farming.
(c) What value of Surjeet is seen in the above act?
Answer:
(a) The common pesticide is DDT.
(b) Organic farming: It is a farming system with minimal or no use of chemicals as fertilizers, herbicides, pesticides etc.
Chemical farming: Generally, chemicals are used as fertilizers, herbicides, pesticides etc. to increase crop yield.
(c) Surjeet showed the value of responsible person, leadership quality, initiative taker and a concerned citizen

Question 3. Large number of Bhetki fish died and got crushed in the turbines of hydroelectric power stations while they migrated from river to sea. The environmentalist gave power plant the solution to this problem. Now all Bhetki fish is removed with the help of special technique and hence do not enter the turbines to crush and die.
(a) What is pisciculture?
(b) Suggest two different varieties of fish.
(c) What value of environmentalist is reflected in the above case?
Answer:
(a) The rearing of fish on large scale is called pisciculture.
(b) Two varieties of fish are bony and cartilaginous.
(c) Environmentalist showed the value of concerned and caring individuals.

Question 4. A group of gardening club students prepared a kitchen garden in the school campus and did organic farming to grow the vegetables. Then the students presented their group work in the assembly to spread the awareness and make students understand the importance of organic products.
(a) What is horticulture?
(b) What is green manure?
(c) State the values of gardening club students.
Answer:
(a) Production of vegetables and fruits commercially is called horticulture.
(b) The green plants like guar or sun hemp are turned into the soil which enriches the soil with nitrogen and phosphorus and is called green manure.
(c) Values of gardening club students are aware individuals and responsible behaviour.

NCERT Solutions for Class 9 Science Chapter 14 Natural Resources

NCERT Solutions Class 9 Science Chapter 14 Natural Resources – Here are all the NCERT solutions for Class 9 Science Chapter 14. This solution contains questions, answers, images, step by step explanations of the complete Chapter 14 titled Natural Resources of Science taught in class 9. If you are a student of class 9 who is using NCERT Textbook to study Science, then you must come across Chapter 14 Natural Resources. After you have studied lesson, you must be looking for answers of its questions. Here you can get complete NCERT Solutions for Class 9 Science Chapter 14 Natural Resources in one place. For a better understanding of this chapter, you should also see Chapter 14 Natural Resources Class 9 notes , Science.

Topics and Sub Topics in Class 9 Science Chapter 14 Natural Resources:

  1. Natural Resources
  2. The Breath of Life: Air
  3. Water: A Wonder Liquid
  4. Mineral Riches in the Soil
  5. Biogeochemical Cycles
  6. Ozone Layer

These solutions are part of NCERT Solutions for Class 9 Science. Here we have given Class 9 NCERT Science Textbook Solutions for Chapter 14 Natural Resources.

NCERT Solutions for Class 9 Science Chapter 14 Natural Resources 1
Page: 193
Question 1. How is our atmosphere different from the atmosphere on Venus and Mars? (SA II – 2013)
Answer: Our atmosphere contains a mixture of many gases like nitrogen (78.08%), oxygen (20.95%), carbon dioxide (0.03%) and water vapor (in varying proportion). Whereas the atmosphere on Venus and Mars is mainly comprised of carbon dioxide. This carbon dioxide constitutes up to 95-97% of the atmosphere on Venus and Mars. It is supposed that due to this reason no life is known to exist on these planets.

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Question 2. How does the atmosphere act as a bblanket?(SA II – 2012, 13)
Answer: It is a known fact that, air is a bad conductor of heat and our atmosphere contains mainly the air. Due to this reason, the atmosphere keeps the average temperature of the Earth fairly steady during the day and even during the course of the whole year. The atmosphere prevents the sudden increase in temperature during the daylight hours and during the night, it slows down the escape of heat into outer space.

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Question 3. What causes winds ? (SA II – 2012, 13)
Answer: Winds are caused due to unequal heating of atmospheric air. This phenomena can be easily seen near coastal regions during the daytime. The air above the land gets heated faster and starts rising. As this air rises, a region Of low pressure is created and air over the sea moves into this area Of low pressure. The movement of air from one region to the other Creates winds. During the day, the direction of the wind would be from the sea to the land.

Question 4. How are clouds formed ? (SA II – 2013)
Answer:The water evaporates due to heating up Of water bodies and other biological activities. The air also heats and rises. On rising, it expands and cools to form tiny droplets. These droplets grow bigger, expand and form clouds. The collection Of dust and other suspended particles facilitate the process.

Question 5. List any three human activities that you think would lead to air pollution. (SA II – 2013)
Answer: Human activities that would lead to air pollution
(i) Excessive use and burning of fossil fuels like coal and petroleum produces different oxides of nitrogen and sulphur. These are not only dangerous to our respiratory system but also leads to acid rain.
(ii) Incomplete combustion of various fuels forms unburnt carbon particles which lowers the visibility, especially in cold weather when water also condenses Out of air. This is known as smog and is a visible indication Of air pollution.
(iii) Large usage Of automobiles and improperly tuning of engines leads to the formation of carbon monoxide gas and Other oxides of nitrogen which causes lot of respiratory problems.
(iv) Forest fires, excessive mining and ore refining, excessive use of chlorofluorocarbons and excessive industrialisation leads to air pollution.

Page 194:
Question 1. Why do organisms need water ? (SA II – 2012)
Answer: Organisms need water due to the following
(i) All cellular processes take place in a water medium.
(ii) All the reactions that take place within our body and within the cells occur between substances that are dissolved in water.
(iii) Substances are also transported from one part of the body to the other in a dissolved form.
(iv) Water makes up about 70% of body weight Of all living organisms.
(v) It helps in the digestion of food and absorption of nutrients in the blood. Hence, organisms need to maintain the level of water within their bodies in order to stay alive. It helps in maintaining body temperature.
Question 2. What is the major source of freshwater in the city/town/village where you live ?
Answer: The major sources of freshwater in the city (town/ village is the underground water which is mostly taken out with the help of hand pumps or tube wells. The rivers flowing in the nearby areas, lakes and ponds also serve as the source of freshwater.

Question 3. DO you know any activity which may be polluting these water sources?
Answer: There are many activities which cause pollution Of water sources such as :
(i) Dumping of waste from factories, sewage from our towns and cities into rivers or lakes.
(ii) Discharging hot water from cooling towers into the water bodies affect the breeding capacity of aquatic organisms.

Page 196
Question 1. How is soil formed ? (SA II – 2013, 2014)
Answer: The formation of soil takes place in this way :
Over long periods of time, thousands and millions Of years, the rocks at or near the surface of the are broken down by various physical, chemical and some biological processes. The end product of this breaking down is the fine particles of soil. There are many other factors which play a vital role in the formation of soil. These factors are :
(i) The Sun : It causes heating of rocks which causes cracking and ultimately breaking up into smaller pieces.
(ii) Water: It breaks rocks both by freezing and fast flow.
(iii) Wind : It causes erosion of rocks similar to as done by fast flowing water. It also carries sand from one place to the other like water does.
(iv) Living organisms : Lichens and moss plants grow on the rock surface and cause rock surface to powder down and form a thin layer of soil. The roots of big trees sometimes go into cracks in the rocks and as the roots grow bigger, the crack is forced bigger.

Question 2.What is soil erosion ? (SA II 2012)
Answer: The removal of topsoil which is rich in humus and nutrients by flowing water or wind is known as soil erosion. If this process continues further then all soil may get washed away and the rocks underneath may get exposed. It may lead to the loss of all valuable resources because nothing grows as such on the rocks.

Question 3. What are the methods of preventing or reducing soil erosion ? (SA II – 2012)
Answer: The methods of preventing soil erosion are :
(i) Afforestation : Forests reduce erosion as the roots of trees hold the soil in place.
(ii) Shelter belts : Trees planted in lines or hedges around farmland reduce erosion by reducing the speed of the wind.
(iii) Contour ploughing : Farmers plough land so that furrows lie across the natural slope of the land. These furrows trap water and do not allow it to flow down carrying the topsoil.
(iv) Terrace (or step) farming : A terraced hillside is less likely to be eroded than a natural hillside. Here a series of steps formed by horizontal strips supported by walls, catch the descending water. It gives the water sufficient time to percolate into the soil and nourish the crop.
(v) Soil cover : Soil left bare after harvesting a crop is often covered with dried vegetation to prevent erosion. Steep slopes that cannot be ploughed are covered with grass or pasture crops.
(vi) Preventing overgrazing : As the grass has a tendency to bind soil molecules, so even a very little grass on a field prevents erosion of soil. But if the grass is overgrazed, it exposes the soil to erosion.

Page 201
Question 1. What are the different states in which water is found during the water cycle? (SA II – 2011)
Answer: All three different states of water can be seen during the water cycle. These states are :
(i) Gaseous state (In the form Of water vapour which evaporates from the surface water). Liquid state (It is formed by the condensation of water vapour and can be Seen in the form of rain).
(ii) Solid state (It is formed by the freezing Of liquid droplets in the upper layer of atmosphere which can be seen in the form Of snow, hail Or sleet).

Question 2. Name two biologically important compounds that contain both oxygen and nitrogen. (SA II – 2011)
Answer: Proteins and nucleic acids (DNA and RNA).

Question 3. List any three human Which would lead to an increase in the carbon dioxide content of air. (SA II – 2011)
Answer: Three human activities which would lead to an increase in the C02 content of air are :
(i) Respiration : It is the natural process Of release Of C02 by both plants and animals. But this release is neither dangerous nor it has any adverse effect on our environment.
(ii) Combustion of fuels : The various types of fuels are burnt to provide energy for various needs like heating, cooking, transportation and industrial fuels.
(iii) Deforestation : Trees help in the conversion Of C02 into organic compounds such as glucose, starch, etc., by the process of photosynthesis. When these trees are cut non-judiciously, then the level of C02 increases in our environment.

Question 4. What is the greenhouse effect ? (SA II – 2011)
Answer: Some gases prevent the escape of heat from the Earth. An increase in the percentage Of such gases in the atmosphere would cause the average temperatures to increase worldwide and this is called the greenhouse effect.

Question 5. What are the two forms of oxygen found in the atmosphere ? (SA II 2011)
Answer: (i) Elemental oxygen is normally found in the form Of a diatomic molecule (02) in the lower regions Of the atmosphere to the extent of 21 %. It is non-poisonous form Of oxygen.
(ii) But in the upper reaches Of the atmosphere (stratosphere), it occurs in the form of ozone, containing three atoms of oxygen and having the molecular formula 03. It is the poisonous form of oxygen.
Some other forms of Oxygen :
It also Occurs extensively in the combined form in the Earth’s crust as well as also in the air in the form of carbon dioxide. In the crust, it is found as the oxides of most metals and silicon, and also as carbonate, sulphate, nitrate and other minerals. It is also an essential component Of most biological molecules like carbohydrates, proteins, nucleic acids and fats (or lipids).

Question 1. Why is the atmosphere essential for life (SAII – 2011)
Answer: Atmosphere is essential for life because of the following masons :
(i) It keeps the average temperature of the earth fairly steady during the day and even during the course of the whole year.
(ii) It prevents the sudden increase in temperature during the daylight hours.
(iii) It contains all the important gases which are required for sustaining life on earth.
These gases are :
(a) Oxygen for respiration of living organisms and oxidation.
(b) Carbon dioxide for photosynthesis in plants and for making food.
(c) Nitrogen for providing inert atmosphere and making proteins.
(iv) The stratosphere region (16-23 km from the surface of Earth) of atmosphere contains a thick layer of ozone which filters the harmful UV radiation from Sun. If these radiations reach on the surface of Earth, then they may cause cancer in animals and are also harmful for plants.

Question 2. Why is water essential for life ? (SAII – 2011)
Answer: Water is considered essential for life because of the following reasons :
(i) All cellular processes take place in water medium.
(ii) All the reactions that take place within our body and within the cells occur between substances that are dissolved in water.
(iii) Substances are also transported from one part of the body to the other in a dissolved form.
(iv) Water makes up about 70% of body weight of all living organisms.
(v) It helps in the digestion of food and absorption Of nutrients in the blood. Hence, organisms need to maintain the level of water within their bodies in order to stay alive.
(vi) It helps in maintaining body temperature.

Question 3. How are living organisms dependent on the soil? Are organisms that live in water totally independent Of soil as a resource ?
Answer: Living organisms are dependent on the soil in the following ways :
(i) Soil provides a natural habitat for various different organisms (such as bacteria, fungi, algae) which help in improving the quality of the soil. Thus, they maintain the fertility of the soil.
(it) Number of insects, animals like rats, rabbits, etc., build their home in the soil.
(iii) Earthworms perform all their activities in the soil. They maintain fertility also as their excreta is rich in nitrogen.
(iv) Soil provides anchorage and nutrients to the plants for their growth and development.
Yes, all organisms that live in water are totally dependent on soil as a resoure :
The mineral nutrients are present in water in the dissolved form. But their recycling takes place only with the help Of decomposers which are present in the soil beds. Thus, all water bodies has soil beds which contain decomposers for the recycling of nutrients and to convert them into readily absorbable forms.

Question 4. You have seen weather reports on television and in newspapers. How do you think we are able to predict the weather?
Answer: Weather observatories collect information regarding the pattern of temperature, speed of wind, air pressure, ocean features and all other features which can affect the weather. This information is collected by remote sensing and weather forecasting satellites. The information collected is then sent to the meteorological departments which prepare a weather report which is displayed on the maps. This information is further transmitted through radio and television.

Question 5. You might have heard about weather report saying ‘depressions’ in the Way of Bengal have caused rains in some areas. We know that many human activities lead to increasing levels of pollution of the air, water bodies and soil. Do you think that isolating these activities to specific and limited areas wcwld help in reducing pollution ?
Answer: Yes, definitely if these activities are isolated to specific and limited areas, then the level of pollution Of the air, water bodies and soil will ‘decrease. For example
(i) If all the sewage discharge, industrial waste is collected and treated properly before diScharging into water bodies, then obviously aquatic life in these water bodies will be affected to a little extent.
(ii) If hot water from the industries (which is used for cooling machines and other devices) is collected at a common place and cooled and aerated properly before discharging into water bodies. Then this will not affect the breeding capacity of aquatic organisms.
(iii) If all the industries and commercial places of a city/town are located in a particular area which is far away from a residential area. Then all diseases resulting from air pollution could be minimised.
(iv) Above all, if we use only biodegradable substances, then they will get decomposed easily and there will be very little pollution of our precious natural resources.

Question 6. Write a note on how forests influence the quality “four air, soil and water resources.
Answer: Forests influence the quality of air, soil and water resources in the following ways :

  1. Influence of forests in controlling the quality of air :
    (a) Forests help in minimising the level of C02 in the atmosphere. This prevents greenhouse effect and global warming.
    (b) Forests reduce environmental temperature which in turn increases the rate of photosynthesis in plants in the surrounding regions.
    (c) Some of the trees has the ability to absorb harmful gases present in the atmosphere, e.g., Jamun trees can absorb compounds of lead easily.
  2.  Influence of forests in controlling the quality of soil :
    (a) The roots of huge trees larger area and prevent erosion of topsoil by holding the soil particles tightly.
    (b) Forests also regulate biogeochemical cycles which are responsible for cycling of nutrients and making them available for the plants in the soil,
    (c) Many of the decomposing bacteria and nitrogen-fixing bacteria live in close association with the roots of the trees.
  3. Influence of forests in controlling the quality of water :
    (a) Forests help in returning pure water back to the surface of earth through rains
    (b) Forests help in maintaining the water cycle as well as water resources of the earth.

NCERT Solutions for Class 9 Science Chapter 14 Natural Resources (Hindi Medium).

9 Science Chapter 14 Natural Resources Intext Questions पेज 217 के उत्तर
9 Science Chapter 14 Natural Resources Intext Questions पेज 219 के उत्तर
9 Science Chapter 14 Natural Resources Intext Questions पेज 222 के उत्तर
9 Science Chapter 14 Natural Resources Intext Questions पेज 226 के उत्तर
9 Science Chapter 14 Natural Resources अभ्यास के प्रश्न उत्तर
9 Science Chapter 14 Natural Resources अभ्यास के प्रश्न उत्तर guide
9 Science Chapter 14 Natural Resources Exercises Questions

NCERT Solutions for Class 9 Science Chapter 13 Why Do We Fall Ill

NCERT Solutions Class 9 Science Chapter 13 Why Do we Fall Ill – Here are all the NCERT solutions for Class 9 Science Chapter 13. This solution contains questions, answers, images, step by step explanations of the complete Chapter 13 titled Why Do we Fall Ill of Science taught in class 9. If you are a student of class 9 who is using NCERT Textbook to study Science, then you must come across Chapter 13 Why Do we Fall Ill. After you have studied lesson, you must be looking for answers of its questions. Here you can get complete NCERT Solutions for Class 9 Science Chapter 13 Why Do we Fall Ill in one place. For a better understanding of this chapter, you should also see Chapter 13 Why Do we Fall Ill Class 9 notes , Science.

Topics and Sub Topics in Class 9 Science Chapter 13 Why Do We Fall Ill:

  1. Why Do We Fall Ill
  2. Health and its Failure
  3. Disease and Its Causes
  4. Infectious Diseases

These solutions are part of NCERT Solutions for Class 9 Science. Here we have given NCERT Solutions for Class 9 Science Chapter 13 Why Do We Fall Ill.

In-Text Questions Solved

NCERT Textbook for Class 9 Science – Page 178:
Question 1. State any two conditions for good health 
Answer: Two conditions essential for good health are:

  1. State of physical, mental and social well-being.
  2. Better surroundings or -environment.

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Question 2. State any two conditions essential for being free of disease.
Answer. The two conditions essential for being free of disease are:

  1. Personal and -domestic .hygiene.
  2. Clean environment and surroundings

Question 3. Are the answers to the above questions necessarily the same or different ? Why ?
Answer: The answer to the above questions are different because a person may be free of disease but his mental, social or economical health may not be good.

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Class 9 Science NCERT Textbook – Page 180
Question 1. List any three reasons why you would think that you are sick and ought to see a doctor. If only one of these symptoms were present, would you still go to the doctor? Why or why not?
Answer: The 3 reasons why one would think that he is sick are—(1) headache, (2) cold and cough, (3) loose-motions.
This indicates that there may be a disease but does not indicate what the disease is. So one would still visit the doctor for the treatment and to know the cause of above symptom.
Even in case of single symptom one needs to go to the doctor to get proper treatment.

Question 2. In which of the following case do you think the long-term effects on your health are likely to be most unpleasant?

  • If you get jaundice
  • If you get lice
  • If you get acne.

Why.
Answer: In the above cases, lice and acne are acute problems of our health which can be cured in short duration. But jaundice is the disease that can have most unpleasant effect on our health as it affects the most important organ of our body i.e., liver. This disease is a chronic one.

NCERT Textbook for Class 9 Science – Page 187
Question 1. Why are we normally advised to take bland and nourishing food when we are sick?
Answer: We are advised to take bland and nourishing food when we are sick because our body needs energy to release cells to overcome the infection, the wear and tear of body organ. The nourishing food provides nutrients to our body that will further provide energy and make new cells. No spices in the food makes its digestion process faster, does not release acids in the body that can interfere in the treatment and cure.

Question 2. What are the different means by which infectious diseases are spread?
Answer: The different means by which infectious diseases spread are:
(a) Through air: They are also called air-borne diseases. The air carries bacteria, virus and the diseases that can be caused are: common cold, influenza, tuberculosis etc.
(b) Through food and water: When one eats/drinks contaminated food/water, that contains bacteria, virus, worm etc. it can cause diseases like cholera typhoid, hepatitis.
(c) Through contact: Many diseases spread by contact of infected person with the healthy person. Example, fungal infections, skin diseases, scabies etc.
(d) By sexual contact: Many diseases can be transmitted, example, syphilis, AIDS.
(e) By body fluids: Fluids like blood, semen, mother’s milk, when infected,
can also cause diseases. Example, AIDS.
(f) Vectors: The organism that spreads a disease by carrying pathogens from one place to another is called vector. Example, mosquitoes are vectors that carry pathogens like protozoa.

Question 3. What precautions can you take in your school to reduce the incidence of infectious diseases?
Answer: The precautions that one can take in school to reduce the incidence of infectious diseases are
(a) By using handkerchief while coughing sneezing.
(b) Washing hands before eating tiffins.
(c) Staying at home if anyone suffers from infectious diseases.
(d) Getting vaccinated before the infection affects.
(e) Keeping the school surroundings clean, checking for stagnant water.

Question 4. What is immunisation?
Answer: When the body attains immunity against any disease, due to vaccination. This process is called immunisation.

Question 5. What are the immunisation programmes available at the nearest health centre in your locality? Which of these diseases are the major health problems in your area?
Answer: The immunization programmes available at the nearest health care centres are:

  1. Child immunization programme starts from 0 to 12 years.
  2. Polio eradication programme
  3. H1N1 screening programme
AgeImmunisation
Infant 6 weeks—9 weeks 9-12 monthsPolio, B.C.G D.P.T, tetanus booster doses, chickenpox, hepatitis A, B etc.

In major areas tuberculosis cases are reported in a large number which is a major concern.

Questions From NCERT Textbook for Class 9 Science

Question 1. How many times did you fall ill in the last one year? What were the illnesses?
(a) Think of one change you could make in your habits in order to avoid any of/ most of the above illnesses.
(b) Think of one change you would wish for in your surroundings in order to avoid any of/most of the above illness.
Answer: The illness was 2-3 times, common-cold, occurred in a year.
(a) One change I would make in my habits in order to avoid the above illness is that I would take proper diet rich in vitamin C and would avoid too cold food.
(b) The surroundings should be neat, and clean,

Question 2. A doctor/nurse/health worker is exposed to more sick people than others in the community. Find out how she/he avoids getting sick herself/himself?
Answer: A doctor/nurse/health worker when exposed to sick people they keep their nose and mouth covered, take care of hygiene, wash hands with soap before drinking water or eating food. They use mask, gloves, etc to avoid the direct contact with the person suffering from infectious diseases.

Question 3. Conduct a survey in your neighbourhood to find out what the three most common diseases are. Suggest three steps that could be taken by your local authorities to . bring down the incidence of these diseases.
Answer:

Common-diseases In neighbourhoodSteps to bring down the diseases spread
1. Malaria 2. Typhoid 3. Cough and cold1. Clean surrounding 2. Clean drinking water 3. Childhood immunisation

Question 4. A baby is not able to tell bis/her.caretakers that she/he is sick. What would help us to find out
(a) that the baby is sick?
(a) what is the sickness?
Answer:
(a) The symptoms like body temperature, fever, cough, cold, loose-motions, non-stop crying improper or no food intake etc. would help up to find that the baby is sick.
(b) The symptoms could help us to find out the sickness of the body.

Question 5. Under which of the following conditions is a person most likely to fall sick?
(a) When she is recovering from malaria.
(b) When she has recovered from malaria and is taking care of someone suffering from chicken-pox.
(c) When she is on a four-day fast after recovering from malaria and is taking care of someone suffering from chicken-pox.
Why?
Answer: (c) When she is on a four-day fast after recovering from malaria and is taking care of someone suffering from chicken-pox.
As the person is not taking proper diet which is required for her proper health and healing of body.
Her chances of getting chicken-pox also high as her body’s immunity has lowered.

Question 6. Under which of the following conditions are you most likely to fall sick?
(a) When you are taking examinations.
(b) When you have travelled by bus and train for two days.
(c) When your friend is suffering from measles.
Why?
Answer: (c) When your friend is suffering from measles, as it is an infectious disease.

NCERT Solutions for Class 9 Science Chapter 13 Why Do we Fall Ill (Hindi Medium)

NCERT Solutions for Class 9 Science Chapter 13 Why do we fall ill Intext questions page 210 in hindi
NCERT Solutions for Class 9 Science Chapter 13 Why do we fall ill अभ्यास के प्रश्न उत्तर
NCERT Solutions for Class 9 Science Chapter 13 Why do we fall ill अभ्यास के प्रश्न उत्तर guide free
NCERT Solutions for Class 9 Science Chapter 13 Why do we fall ill
NCERT Solutions for Class 9 Science Chapter 13 Why do we fall ill Intext questions page 210
NCERT Solutions for Class 9 Science Chapter 13 Why do we fall ill Intext questions page 187 in english medium free
NCERT Solutions for Class 9 Science Chapter 13 Why do we fall ill Intext questions page 187 in pdf form
NCERT Solutions for Class 9 Science Chapter 13 Why do we fall ill Intext questions page 180
NCERT Solutions for Class 9 Science Chapter 13 Why do we fall ill Intext questions page 178
NCERT Solutions for Class 9 Science Chapter 13 Why do we fall ill Intext questions page 187 in english medium free

More Questions Solved

NCERT Solutions for Class 9 Science Chapter 13 Multiple Choice Questions

Choose the correct option:
1. The disease that affects our lungs is
(a) AIDS (b) rabies
(c) polio (d) tuberculosis
2. The BCG vaccine is given for the immunity against
(a) hepatitis       (b) jaundice
(c) tuberculosis (d) malaria
3. Malaria is caused due to
(a) protozoa (b) Anopheles mosquito
(c) both (a) and (b) (d) none of the above
4. Trypanosoma, Leishmania and Plasmodium are the examples of
(a) virus (b) bacteria
(c) protozoa (d) worm
5. Diarrhoea, cholera, typhoid, are the diseases that have one thing in common, that is:
(a) All of them are caused by bacteria.
(b) All of them are transmitted by contaminated food and water.
(c) All of them are cured by antibiotics.
(d) All of the above.
6. The bacteria among the following is
(a) Plasmodium (b) Trypanosoma
(c) Rabies virus (d) Salmonella typhi
7. HIV virus attacks one of the following cells in our body:
(a) Red blood cell (b)White blood cell
(c) Liver cell (d) Long cell
8. The pathogens of disease are
(a) bacteria (b) virus
(c) protozoa(d) all of the above
9. Penicillin is a drug that can
(a) interfere in thq biological pathway of bacteria
(b) an antibiotic that can kill bacteria
(c) both (a) and (b)
(d) none of the above
10. The disease caused due to worm is
(a) tetanus (b) rabies
(c) sleeping sickness (d) filariasis
Answer. 1—(d), 2—(c), 3—(c), 4—(c), 5—(d), 6—(d),10—(d).

NCERT Solutions for Class 9 Science Chapter 13 Very Short Answer Type Questions

Question 1. Define health.
Answer. Health means a state of physical, mental and social well-being.

Question2. Define disease.
Answer: Disease means being uncomfortable.

Question 3. What do you mean by symptoms of disease?
Answer: Symptoms of disease are the signs of a disease which indicates the presence of a particular disease.

Question 4. What are acute diseases?
Answer: Those diseases which last for very short period of time are called acute diseases. Example, headache and cold.

Question 5. What are chronic diseases?
Answer: The diseases which last for very long period of time are called chronic disease Example, tuberculosis and jaundice.

Question 6. What are pathogens?
Answer: The disease causing microbes are called pathogens. Example, bacteria, virus, fungi, worms.

Question 7. What are vectors?
Answer: The organisms that spread or carry pathogens from one place to another, from infected person to healthy person is called vector.
Example, mosquito, housefly etc.

Question 8. What are infectious diseases?
Answer: Diseases which can spread from one person to another and microbes are the immediate cause for these diseases are called infectious diseases. Example, typhoid

Question 9. What are non-infectious diseases?
Answer: Diseases which do not spread from one person to another is called non-infectious diseases. Example, cancer.

Question 10. Name any one disease caused due to genetic abnormality.
Answer: Haemophilia.

Question 11. Name two diseases caused by protozoa.
Answer: Malaria and amoebiasis.

Question 12. Name two diseases caused due to bacteria.
Answer. Tuberculosis, typhoid.

Question 13. Name two disease caused due to virus.
Answer: Polio, chickenpox.

Question 14. Name two disease caused by fungi.
Answer: Scabies and skin infection.

Question 15. What are antibiotics?
Answer: Antibiotics are drugs that block the biochemical pathways important for bacteria. These are used to cure diseases caused due to bacteria.

Question 16. Give the full form of AIDS.
Answer: AIDS-Acquired Immuno Deficiency Syndrome (Syndrome means collection of symptoms).

Question 17. Name the pathogen that causes sleeping sickness.
Answer: The protozoan → Trypanosoma.

Question 18. Name the organism that causes kala-azar.
Answer: Leishmania.

Question 19. Name two air-borne diseases.
Answer: Common cold, cough,* tuberculosis.

Question 20. Name two diseases that are organ specific.
Answer:
Jaundice – liver
Tuberculosis – lungs

Question 21. Which virus causes AIDS?
Answer: HIV virus causes AIDS
HIV—Human Immuno Deficiency Virus.

NCERT Solutions for Class 9 Science Chapter 13 Short Answer Type Questions

Question 1. Give the difference between acute disease and chronic disease.
Answer:

Acute diseaseChronic disease
1. It may last for few days. 2. It does not have major effect on body.1. It lasts for longer period. 2. It affects the body drastically.

Question 2. State two main causes of disease.
Answer: Two main causes of disease are immediate cause and contributory cause. Immediate cause: This is due to the organisms that enter our body and cause disease. Example, virus, protozoa, bacteria.
Contributory cause: These are the secondary factors which lead these organisms to enter our body. Example, dirty water, unclean surrounding, contaminated food etc.

Question 3. Define vaccine and name two vaccines.
Answer: Vaccine is a chemical /drug given in advance to a body to give immunity against certain diseases.
Vaccines given to children are:
(a) BCG—for tuberculosis prevention
(b) Polio drops—for polio prevention

Question 4. What is antibiotic penicillin? Give its function.
Answer: Penicillin antibiotic blocks the bacterial processes that build the cell wall. Due to this drug, the bacteria is unable to make a protective cell wall and dies easily. It is used to cure the diseases and infections caused by bacteria.

Question 5. Bacteria is a cell, antibiotics can kill these bacteria (cell), Human body is also made of cells how does it affect our body?
Answer: Antibiotics block the biochemical pathway of bacteria by which it makes a protective cell wall around it. Antibiotic does not allow the bacteria to make this cell wall because of which they die.
Human body cell don’t make any cell wall so antibiotics cannot have any such effect on our body.

Question 6. How does cholera becomes an epidemic in a locality?
Answer: Cholera is an infectious disease that spreads due to unsafe water. It can spread in a locality; if a person suffering from cholera lives in the locality and
the excreta of this person, get mixed with the drinking water used by people living nearby. The cholera-causing microbe enters the new hosts through the water they drink and cause disease in them.

Question 7. Name the organs affected due to the following diseases:
Malaria, jaundice, Japanese encephalitis, typhoid.
Answer:

  1. Malaria: Infects liver and red blood cells
  2. Jaundice: Infects the liver.
  3. Japanese encephalitis: Infects the brain
  4. Typhoid: Infects blood.

Question 8. Why are sick patients advised to take bed rest?
Answer: Doctors advise to take bed rest for sick patients so that they can conserve their energy which can be used for healing of their body organs which were affected due to certain disease.

Question 9. How do we kiU microbes that enter our body and cause diseases?
Answer: Microbes can be killed by using medicines These microbes are of different categories—virus, bacteria, fungi or protoza. Each of these groups of organisms have some essential biochemical life processes which is peculiar to a particular group and is not shared by others. These pathways are not used by us. By using drugs that blocks the microbial synthesis pathway without affecting us can kill the microbes.

Question 10. What are disease specific means of prevention?
Answer: The disease specific means of prevention are the use of vaccines. The vaccines, are used against tetanus, diphtheria, whooping cough, measles, polio and many others.

Question 11. Why can’t we make antiviral medicines/drugs?
Answer: The viruses lie on the border line of living and non-living organisms. The viruses can live, grow and multiply only inside the host body. They cannot be grown or cultured and their .biological pathways cannot be affected. Hence, the antiviral medicines/drugs is difficult to make.

Question 12. Write a short note on malaria as a disease, its symptoms and control.
Answer: Malaria is caused by protozoa that lives in blood. This parasite enters our body through a female Anopheles mosquito bite which is the vector, visits water to lay eggs, the protozoa enters our blood stream when female mosquito bites us. This protozoa affects our liver and red blood cells.
Symptoms: Very high fever with periodic shivering, headache and muscular pain. –
Control: Use of quinine drug, keeping the surroundings clean with no stagnant water, use of mosquito repellent creams, nets, can control the spread of this disease.

Question 13. What is AIDS? How does a person get affected with HIV?
Answer: AIDS is Acquired Immuno Deficiency Syndrome, it is caused due to HIV— human immuno deficiency virus. This virus reduces the immunity of human body. Therefore if any microbe enters the body of a person it causes disease killing the person.
The virus is transmitted from infected person to other person by any of the following way:
(a) Blood transfusion.
(b) From mother (infected) to baby in the womb.
(c) From mother’s milk to lactating baby.
(d) By sexual contact.
(e) Sharing of needle with an infected person.

Question 14. Becoming exposed to or infected with an infectious microbe does not necessarily mean developing noticeable disease. Explain.
Answer: This is because the immune system of our body is normally fighting off microbes. Our body have cells that are specialised in killing infecting microbes. Whenever any microbes or foreign body enters our system, these cells become active and kill the microbes that could cause any damage to the body. These immune cells manage to kill off the infection and a person does not get disease.

Question 15. What are three limitations for the approach to deal with infectious diseases?
Answer: The three limitations are:
(1) If someone has a disease, their body functions are damaged and may never recover completely.
(2) As the treatment will take time, the person suffering from a disease is likely to be bedridden for some time.
(3) The infectious person can serve as the source from where the infection may spread to other people.

Question 16. Give the common methods of transmission of diseases.
Answer:
NCERT Solutions for Class 9 Science Chapter 13 Why Do We Fall Ill SAQ Q16
The common methods of transmission of diseases are:
(1) By air – cough, cold, tuberculosis
(2) By food and water – typhoid, jaundice
(3) By mosquito bite – malaria
(4) By rabid animal – rabies
(5) By direct contact – skin infection, small pox, AIDS
(6) By indirect contact – typhoid, chickenpox

Question 17. What are the basic conditions for good healths?
Answer: The basic conditions for good health are:
(1) Proper balanced and nutritious diet
(2) Personal hygiene
(3) Clean surroundings and clean environment
(4) Regular rest
(5) Proper rest
(6) Good economic status.

NCERT Solutions for Class 9 Science Chapter 13 Long Answer Type Questions

Question 1. If someone in the family gets infectious disease, what precautions will you advice to the other family members?
Answer: For an infectious diseased person in the family following precautions should be taken:
(1) The surroundings and the house should be clean.
(2) The infected person should be kept isolated in a separate room.
(3) The clothes and utensils of patient should be sanitized regularly.
(4) Separate towels and handkerchief should be used by the patient.
(5) Children should not be allowed to visit the infected person.
(6) Clean and boiled drinking water should be given to the patient.
(7) A balanced and nutritious diet which will provide lot of energy should be given.
(8) There should be silence and the patient should be given lot of bedrest to overcome the infection.

Question 2. What is a disease? Classify disease based on duration and infection cause.
Answer: Disease can be defined as the state of human health which is not at ease is not comfortable. During disease, the functioning or appearance of one or more systems of the body changes.
Classification:
(a) Based on duration:
Acute diseases: Diseases that last for only short period of time. Example, headache, common cold etc.
Chronic diseases: Diseases that last for long time is called chronic disease Example, tuberculosis.
(b) Based on cause: Disease can be grouped as infectious/communicable disease and non-infectious or non-communicable disease.
Infectious diseases: These diseases are caused due to microbes and can spread from one person to another.
Non-infectious diseases: These type of diseases do not spread in the community, but remains internal. Example, cancer, genetic abnormalities.

Question 3. What are the different ways used for the treatment and prevention of diseases?
Answer: Principles of treatment for diseases are:
(1) To reduce the effect of the diseases.
(2) To kill the cause of the disease i.e., to kill the microbes like bacteria, fungi, protozoa.
Principles of prevention are:
(a) General ways: It relate to preventing exposure to the microbes. This can be done in following ways:

  1. For avoiding air-borne infections—Avoid visiting public place, cover your nose and mouth while sneezing or coughing
  2. For water-borne infection—Drink safe, clean and boiled water.
  3. For vector-borne diseases—Keep the surroundings clean, keep food and water covered and clean. Do not allow any water to stand as it becomes a breeding ground for mosquitoes.
  4. Self immunity—It is self-defence mechanism in our system that can fight off and kill microbes that enter our body.

(b) Specific ways—By giving vaccines, childhood immunisation that is given to children for preventing infections and diseases.

Question 4. State the mode of transmission for the following diseases:
Malaria, AIDS, Jaundice, Typhoid, Cholera, Rabies, Tuberculosis, Diarrhoea, Hepatitis, Influenza.
Answer:

SL. No.DiseasesMode of transmission
1.MalariaMosquito bite (female Anopheles mosquito carries protozoa)
2.AIDSInfected blood, semen, mother’s milk, from mother to foetus.
3.JaundiceContaminated water.
4.TyphoidContaminated food and water.
5.CholeraContaminated food and water.
6.RabiesBite of rabid animal.
7.TuberculosisCough and sneeze droplets.
8.DiarrhoeaContaminated food and water.
9.HepatitisContaminated food and water.
10.InfluenzaCough and sneeze droplets.


Question 5. Name all the micro-organisms that causes infectious disease and name few diseases caused by each micro-organism.

Answer:

Infections Micro-organismDisease
BacteriaTuberculosis, typhoid, diarrhoea, cholera
VirusPolio, AIDS, chickenpox
ProtozoaMalaria, amoebiasis, kala-azar, sleeping sickness
FungiFood poisoning, skin diseases

NCERT Solutions for Class 9 Science Chapter 13 Value-Based Questions

Question 1. AIDS is spreading globally at very fast rate, a group of class-IX students made a module on its prevention and posted it on social networking site.
(a) What is the cause of AIDS?
(b) Give any two preventions for it.
(c) What value of these students is reflected in this act?
Answer:
(a) HIV virus.
(b) Two preventive measures of AIDS are use of disposable injections, scanning of blood before transfusion for HIV.
(c) Students showed moral responsibility and general awareness.

Question 2. There is a ban on sale of junk food items in school canteens. A student notices that in his school canteen cold drink, chips and cup noodles were sold. He reports this matter to his teachers and school office. Thereafter the sale of junk food in canteen was stopped and monitored.
(a) Why is balanced diet necessary for maintaining healthy body?
(b) Name two diseases caused due to junk food.
(c) What values of this student is reflected?
Answer:
(a) Balanced diet provides all the nutrients to our body in appropriate amount and keeps our body healthy.
(b) Heart diseases and obesity.
(c) The student showed general awareness and responsible citizen.

Question 3. Sudha’s brother who is 5 years old had high fever for two days, doctor prescribes him antibiotics. Sudha hesitantly asks for the name of the disease his brother had and why was he advised to take antibiotics without any diagnosis?
(a) Is fever a disease?
(b) What is the role of antibiotics?
(c) What value of Sudha is reflected in the above act?
Answer:
(a) Fever is not a disease it is a symptom.
(b) Antibiotics are medicines advised to be taken only when the immune system of a patient is unable to fight against the microbes.
(c) Sudha showed moral responsibility, general awareness.

Question 4. Malaria was on the outbreak in a locality of a town. People thought that the bite of mosquitoes cause malaria and started killing mosquitoes. Anita told the masses to clean the breeding grounds of mosquitoes, to add oil on the water bodies and clean all the areas, where stagnant water was present.
(a) What is the cause of malaria?
(b) Give two ways to prevent it.
(c) What value of Anita is reflected in this act?
Answer:
(a) Malaria is caused due to the protozoa named Plasmodium.
(b) Two ways to prevent malaria are—
(i) Clear all breeding grounds of mosquitoes i.e., stagnant water.
(ii) Use mosquito repellents.
(c) Anita showed the values of social responsibility and self-awareness.

Question 5. Latika was suffering with chickenpox and was advised to stay at home by her doctor. Latika’s friend persuades her to go for class picnic along with her and have fun. But Latika refuses and stays at home.
(a) What is the cause of chickenpox?
(b) Give one precaution for it.
(c) What value of Latika is reflected in not going for picnic.
Answer:
(a) Virus causes chickenpox.
(b) One precaution of avoiding spread of chickenpox is to stay away from public places when one is suffering from it. Take vaccination.
(c) Latika showed moral responsibility and self awareness.

NCERT Solutions for Class 9 Science Chapter 12 Sound

NCERT Solutions Class 9 Science Chapter 12 Sound – Here are all the NCERT solutions for Class 9 Science Chapter 12. This solution contains questions, answers, images, step by step explanations of the complete Chapter 12 titled Sound of Science taught in class 9. If you are a student of class 9 who is using NCERT Textbook to study Science, then you must come across Chapter 12 Sound. After you have studied lesson, you must be looking for answers of its questions. Here you can get complete NCERT Solutions for Class 9 Science Chapter 12 Sound in one place. For a better understanding of this chapter, you should also see Chapter 12 Sound Class 9 notes , Science.

Topics and Sub Topics in Class 9 Science Chapter 12 Sound:

  1. Sound
  2. Production of Sound
  3. Propagation of Sound
  4. Reflection of Sound
  5. Range of Hearing
  6. Applications of Ultrasound
  7. Structure of Human Ear

These solutions are part of NCERT Solutions for Class 9 Science. Here we have given Class 9 NCERT Science Text book Solutions for Chapter 12 Sound.

IN-TEXT QUESTIONS SOLVED

NCERT Textbook for Class 9 Science – Page 162
Question 1. How does the sound produced by a vibrating object in a medium reach your ear?
Answer: Air is the commonest material through which sound propagates. When vibrating objects, like prongs of a tuning fork move forward, they push the molecules of the air in front of them. This in turn compresses the air, thus creating a region of high pressure and high density called compression. This compression in the air travels forward. When the prongs of the tuning fork move backward, they create a region of low pressure in the air, commonly called rarefaction.
This region has low pressure, low density, and more volume. As the tuning fork continues to vibrate, the regions of compression in the air alternate with the regions of rarefaction. These regions alternate at the same place. The energy of vibrating tuning fork travels outward. This energy which reaches the ears, makes the eardrums to vibrate and thus we hear sound

More Resources for CBSE Class 9

NCERT Textbook for Class 9 Science – Page 163
Question 1. Explain how sound is produced by your school bell.
Answer: Air is the commonest material through which sound propagates. When school bell is rung, it pushes the molecules of the air in front of it. This in turn compresses the air, thus creating a region of high pressure and high density called compression. This compression in the air travels forward. When the bell moves back, it creates a region of low pressure in the air, commonly called rarefaction. This region has low pressure, low density, and more volume. As the bell continues to vibrate, the regions Of compression in the air alternate with the regions of rarefaction. These regions alternate at the same place. The energy of vibrating bell travels outward. This energy which reaches the ears, makes the eardrums to vibrate and thus we hear sound.

Question 2. Why are sound waves called mechanical waves ?
Answer: Some mechanical energy is required to make an object vibrate. Sound energy cannot be produced on its own. The mechanical energy Of vibrating object travels through a medium and finally reaches the ear. Therefore, the sound waves are called mechanical waves.

Formulae Handbook for Class 9 Maths and ScienceEducational Loans in India

Question 3. Suppose you and your friend are on the moon. Will you be able to hear any-sound produced by your friend ?
Answer: No, I will not be able to hear sound, because moon has no atmosphere. Therefore, no sound waves can travel to your ears and, therefore, no sound is heard.

Class 9 Science NCERT Textbook – Page -I
Question 1. Which wave property determines (a) loudness, (b) Pitch ?
Answer: (a) The amplitude of the wave determines the loudness; more the amplitude of a wave, more is the loudness produced.
(b) The pitch is determined by the frequency of the wave. Higher the frequency of a wave more is its pitch and shriller is the sound.

Question 2. Guess which sound has a higher pitch; guitar or car horn ?
Answer: Car horn has a higher pitch than a guitar, because sound produced by the former is shriller than the latter.

NCERT TextBook Class 9 Science Page 166 -II
Question 1. What are wavelength, frequency, time period and amplitude of a sound wave ?
Answer: Frequency: The number of compressions or rarefactions taken together passing through a point in one second is called frequency.
Time Period: It is the time taken by two consecutive compressions or rarefactions to cross a point.
Amplitude: It is the magnitude of maximum displacement of a vibrating particle about its mean position.

Question 2. How are the wavelength and frequency of a sound wave related to its speed ?
Answer: Speed of sound Frequency x Wavelength

Question 3. Calculate the wavelength of a sound wave whose frequency is 220 Hz and speed is 440 m s-1 in a given medium.
Answer: Frequency = 220 Hz
Speed of sound = 440 m s-1
We know speed of sound Frequency x Wavelength = 220 x Wavelength
Wavelength = Vϑ = 440220 = 2m

Question 4. A person is listening to a tone of 500 Hz sitting at a distance of 450 m from the source Of the sound. What is the time interval between successive compressions from the source ?
Answer:

Question 5. Distinguish between loudness and intensity of sound.
Answer: The loudness depends on energy per unit area of the wave and on the response of the ear but intensity depends only on the energy per unit area of the wave and is independent of the response of the ear.

Question 6. In which of the three media, air, water or iron, does sound travel the fastest at a particular temperature ?
Answer: Sound travels fastest in iron as compared to water and air.
An echo is returned in 3 s. mat is the distance of the reflecting surface from the source, given the speed of sound is 342 m s-1

Question 7. Why are the ceilings of concert halls curved ?
Answer: The ceilings of concert halls are curved because sound after reflection from it reaches all the corners of the hall and is audible to each person in the hall.

Question.8.What is the audible range of the average human ear ?
Answer. An average human ear can hear sound waves between frequencies 20 Hz to 20,000 Hz.

Question 9. What is the range of frequencies associated with (a) Infra sound ? (b) Ultrasound ?
Answer: (a) Infra sound : Sound waves between the Frequencies 1 and 20 Hz.
(b) Ultrasound : Sound waves of the frequencies above 20,000 Hz.

Extra Questions for CBSE Class 9 Science Chapter 12 Sound

Question 1. What is sound and how is it produced ?
Answer: Sound is mechanical energy which produces a sensation of hearing. When an Object is set into vibrations, sound is produced.

Question 3. Cite an experiment to show that sound needs a material medium for its propagation.
Answer: Take an electric circuit which consists of a cell, a switch and an electric bell arranged inside a bell jar, which stands on the platform of an evacuating pump. The switch of the bell is pressed to close the electric circuit. When there is air within the bell jar, sound is heard. Air is now pumped out of the bell jar. When the air is completely removed from the bell jar, no sound is heard as it is obvious from fig. because the medium of air which has to carry energy from the bell to the bell jar is removed. It shows that sound needs material medium for its propagation.

Question 4. Why is sound wave called a longitudinal wave ?
Answer:Sound wave is called longitudinal wave because the particles of the medium vibrate in the direction of the propagation of wave.

Question 5. Which characteristic of the sound helps you to identify your friend by his voice while sitting with others in a darkroom ?
Answer: The characteristic of sound is quality or timbre.

Question 6. Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen, why ?
Answer: Speed of sound is 330 m/sec in air medium at 0°C. Whereas speed of light is 3 x 108m/sec. When we compare the speed of light with that of speed of sound, speed of light is greater than that of speed of sound. Therefore thunder is heard a few seconds after the flash is seen.

Question 7. A person has a hearing range from 20 Hz to 20 kHz. What are the typical wavelengths of sound waves in air corresponding to these two frequencies? Take the speed of sound in air as 344 ms-1.
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound Extra Questions Q7

Question 8. Two children are a± opposite ends of an aluminium rod. One strikes the end of the rod with a stone. Find the ratio of times taken by the sound wave in air and in aluminium to reach the second child.
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound Extra Questions Q8

Question 9. The frequency of a sources/ sound is 100 Hz. How many times does it vibrate in a minute?
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound Extra Questions Q9

Question 10. Does sound follow the same laws of reflection as light does? Explain.
Answer: Yes. Sound follows the same laws of reflection as that of light because,
(i) Angle of incidence of sound is always equal to that of angle of reflection of sound waves.
(ii) The direction in which sound is incident, the direction in which it is reflected and normal all lie in the same plane.

Question 11. When a sound is reflected from a distant object, an echo is produced. Let the distance between the reflecting surface and the source of sound production remains the same. Do you hear echo sound on a hotter day?
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound Extra Questions Q11
Time is inversely proportional to the speed. As the temperature increases, the speed increases. Thus on a hot day due to high temperature the speed of sound increases. Hence the time will decrease and we can hear the echo sooner.

Question 12. Give two practical applications of reflection of sound waves.
Answer: Reflection of sound is used in megaphones, horns and musical instruments such as trumpets and shehna. It is used in stethoscope for hearing patient’s heartbeat. Ceilings of the concert halls are curved, so that sound after reflection reaches all comers of the hall. (Any two practical applications can be written).

Question 13. A stone dropped from the top of a tower 500 m high into a pond of water at the base of the tower. When is the splash heard at the top? Giving, g = 10 ms-2 and speed of sound = 340 m s-1.
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound Extra Questions Q13

NCERT Solutions for Class 9 Science Chapter 12 Sound Extra Questions Q13.1

Question 14. A sound wave travels at a speed of 339 ms-1. If its wavelength is 1.5 cm, what is the frequency of the wave? Will it be audible?
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound Extra Questions Q14

Question 15. What is reverberation? How can it be reduced?
Answer: The persistence of sound in an auditorium is the result of repeated reflections of sound and is called reverberation.
To reduce the undesirable effects due to reverberation, roofs and walls of the auditorium are generally covered with sound absorbent materials like compressed fiberboard, rough plaster or draperies. The seat materials are also selected having sound absorption properties.

Question 16. What is loudness of sound? What factors does it depend on?
Answer: The loudness of sound is determined by its amplitude. The amplitude of the sound wave depends upon the force with which an object is made to vibrate. Loud sound can travel a larger distance as it is associated with higher energy. A sound waves spreads out from its source. As it moves away from the source its amplitude as well as its loudness decreases.
NCERT Solutions for Class 9 Science Chapter 12 Sound Extra Questions Q16

Question 17. Explain how bats use ultrasound to catch a prey. 
Answer: Bats search out its prey by emitting and detecting reflections of ultrasonic waves. The high-pitched ultrasonic squeaks of bat are reflected from the obstacles or prey and return to bat’s ear. The nature of reflection tells the bat where the obstacle or prey is and what it is like.

Question 18. How is ultrasound used for cleaning?
Answer: Ultrasound is used to clean parts located in hard-to-reach places (i.e.) spiral tube, odd shaped parts, electronic components etc. Objects to be cleaned are placed in a cleaning solution and ultrasonic waves are sent into the solution. Due to the high frequency, the dust particles, grease get detached and drop out. The objects thus get thoroughly cleaned.

Question 19. Explain the working and application of a sonar.
Answer: Working: SONAR Consists of a transmitter and a detector and is installed in a boat or a ship as shown in the fig. The transmitter produces and transmits ultrasonic waves. These waves travel through water and after striking the object on the seabed, get reflected back and are sensed by the detector. The detector converts the ultrasonic waves into electrical signals which are appropriately interpreted. The distance of the object that reflected the sound wave can be calculated by knowing the speed of sound in water and the time interval between the transmission and reception of the ultrasound.
NCERT Solutions for Class 9 Science Chapter 12 Sound Extra Questions Q19

NCERT Solutions for Class 9 Science Chapter 12 Sound Extra Questions Q19.1

Question 20. A sonar device on a submarine sends out a signal and receives an echo 5 s later. Calculate the speed of sound in water if the distance of the object from the submarine is 3625 m.
Answer: Time taken between transmission and reception of signal = 5 sec.
Distance of the object from the sub marine = 3625 m.
NCERT Solutions for Class 9 Science Chapter 12 Sound Extra Questions Q20

Question.21. Explain how defects in a metal block can be detected using ultrasound.
Answer. Ultrasounds can be used to detect cracks and flaws in metal blocks. Metallic components are used in the construction of big structures like buildings, bridges, machines and scientific equipment’s. The cracks or holes inside the metal blocks, which are invisible from outside reduces the strength of the structure. Ultrasonic waves are allowed to pass through the metallic block and detectors are used to detect the transmitted waves. If there is even a small defect, the ultrasound gets reflected back indicating the presence of the flaw or defect.
NCERT Solutions for Class 9 Science Chapter 12 Sound Extra Questions Q21

Question 22. Explain how the human ear works.
Answer: The outer ear is called “pinna. It collects the sound from the surroundings. The collected sound passes through the auditory canal. At the end of the auditory canal there is a thin membrane called the eardrum or the tympanic membrane. When a compression of the medium reaches the eardrum the pressure on the outside of the membrane increases and forces the eardrum inward. Similarly, the eardrum moves outward when a rarefaction reaches it. In this way the eardrum vibrates. The vibrations are amplified several times by three bones (the hammer, anvil and stirrup) in the middle ear. The middle ear transmits the amplified pressure variations received from the sound wave to the inner ear. In the inner ear, the pressure variations are turned into electrical signals by the cochlea. These electrical signals are sent to the brain via the auditory nerve and the brain interprets them as sound.

NCERT Solutions for Class 9 Science Chapter 12 Sound (Hindi Medium)

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9 Science Chapter 12 Sound अभ्यास के प्रश्न उत्तर
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Class 9 Science Chapter 12 Intext Questions page 190
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9 Science Chapter 12 Sound all question answers solved

MORE QUESTIONS SOLVED

NCERT Solutions for Class 9 Science Chapter 12 Multiple Choice Questions 

Question 1. A wave in slinky travelled to and fro in 5 sec the length of the slinky is 5 m. The velocity of wave is
NCERT Solutions for Class 9 Science Chapter 12 Sound MCQ Q1
(a) 10 m/s (b) 5 m/s
(c) 2 m/s (d) 25 m/s
Answer: (c)

Question 2. Loud sound can travel a larger distance, due to
(a) higher amplitude (b) higher energy
(c) high frequency (d) high speed
Answer (c)

Question 3. We can distinguish between sound having same pitch and loudness, this characteristic of sound is
(a) tone (b) note
(c) pitch (d) timber
Answer: (b)

Question 4. Speed of sound depends upon
(a) temperature of medium
(b) pressure of medium
(c) temperature of source producing sound
(d) temperature and pressure of medium
Answer: (d)

Question 5. Speed (s), wavelength’ (X) and frequency (v) of sound are related as
(a) s =u x v (b) v=s x u
(c) u=s x v (d)u=s/v
Answer: (c)

Question 6. To hear a distinct echo the time interval between the original sound and the reflected sound must be:
(a) 0.2 s (b) 1 s
(c) 2 s (d) 0.1 s
Answer: (d)

Question 7. Reverberation of sound is used in
(a) stethoscope (b) trumpets
(c) megaphone (d) all of these
Answer: (d)

Question 8. Children under the age of 5 can hear upto:
(a) 20 kHz (c) 20 Hz
(b) 25 kHz (d) 25 Hz
Answer: (b)

Question 9. Dolphins, bats and porpoise uses
(a) ultrasound (c) both (a) and (b)
(b) infrasound (d) none of these
Answer: (a)

Question 10. The part of human ear that converts sound vibrations into electrical signals are:
(a) Tympanic membrane (c) Stirrup
(b) Hammer (d) Cochlea
Answer: (d)

NCERT Solutions for Class 9 Science Chapter 12 Very Short Answer Type Questions

Question 1. Is sound wave longitudinal or transverse?
Answer: Sound wave is longitudinal in nature.

Question 2. What is the relation between frequency (v) and time period of a sound wave?
Answer: v = 1/T
Frequency is inversely proportional to time period.

Question 3. In which of the three media air, water or steel does sound travel the fastest?
Answer: Sound travels fastest in steel.

Question 4. Which has a higher pitch—the sound of a whistle or that of a drum?
Answer: The sound of whistle has higher pitch.

Question 5. What is pitch?
Answer: The way our brain interprets the frequency of an emitted sound is called the pitch.

Question 6. How can we distinguish one sound from another having the same pitch and loudness?
Answer: The quality or timber of sound helps us to distinguish one sound from another having the same pitch and loudness.

Question 7. What is the audible range of frequency for human beings?
Answer: The audible range of frequencies for human beings is 20 Hz to 20,000 Hz.

Question 8. What is one Hz?
Answer: Hz is the unit of frequency, called as Hertz. One Hertz is equal to one cycle per second.

Question 9. Define speed of sound.
Answer: The speed of sound is defined as the distance travelled per unit time by compression or rarefaction.

Question 10. What is ‘note’ of sound?
Answer: The sound produced due to a mixture of several frequencies is called a note, it is pleasant to listen to.

Question 11. Find the frequency of a wave whose time period is 0.002 second.
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound VSAQ Q11

Question 12. What is the time period-of sound wave?
Answer: The time taken by two consecutive compressions or rarefactions to cross a fixed points is called the time period of the wave.

Question 13. What is the minimum distance required to hear distinct echo?
Answer: The minimum distance of the obstacle from the source of sound should be 17.2 m.

Question 14. What is reverberation?
Answer: The repeated reflection that results in the persistence of sound is called reverberation.

Question 15. What is SONAR?
Answer: SONAR is—Sound Navigation and Ranging. It is a device that uses ultrasonic waves to measure the distance, direction and speed of underwater objects by getting the reflection of sound.

Question 16. What is ‘ultrasonic’ and ‘infrasonic’ sound wave?
Answer: Sound waves with frequencies below the audible range (less than 20 Hz) are termed as “infrasonic” and those sound waves with frequencies above the audible range (more than 20000 Hz) are termed as “ultrasonic”.

Question 17. What should be the time interval between the originated sound and the reflected sound to be heard distinctly?
Answer: To hear a distinct sound the time interval between the originated sound and the reflected sound must be at least 0.1 second.

NCERT Solutions for Class 9 Science Chapter 12 Short Answer Type Questions

Question 1. What is a medium? Give two examples.
Answer: The matter or substance through which sound is transmitted is called a medium. It can be solid, liquid or gas. Example, air, water, metals.

Question 2. Define wave-motion.
Answer: A wave is a disturbance that moves through a medium when the particles of the medium set neighbouring particles into motion. The particles of the medium do not move forward but the disturbance is carried forward.

Question 3. What is ‘sonic boom’?
Answer: When an object just attains a supersonic speed, it causes shock waves in air. As a result there is large change in air pressure. This results in sonic boom.

Question 4. Why does sound become faint with distance?
Answer: Sound is a form of energy. As it moves away from the source its amplitude as well as its loudness decreases. The energy also get transformed in vibration of the particles of the medium.

Question 5. Why do we say that sound waves are longitudinal?
Answer: Longitudinal waves need medium for propagation. The sound energy travel in the same line as the particles oscillate.
———— > Sound energy
<————>Particles oscillation
It forms compression and rarefaction for the longitudinal wave motion. Sound wave shows all the characteristics of longitudinal wave so it is called as longitudinal wave.

Question 6. Differentiate between longitudinal wave and transverse wave.
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound SAQ Q6

Question 7. What is crest and trough?
Answer: When a wave is propagated as represented below. A peak is called the crest and a valley is called the trough of a wave.
NCERT Solutions for Class 9 Science Chapter 12 Sound SAQ Q7

Question 8. The maximum oscillation disturbance of particles of air forms crest and trough. What is echo? Why don’t we get echo in small room?
Answer: The distinct sound heard after reflection of sound from the source is called echo. For echo, the distance of reflecting surface from the source should be more than 17.2 m.

Question 9. What is velocity of sound? Why does sound travel faster in summer season than in winter?
Answer: Velocity of sound is- the speed of sound in a given medium at a given temperature. As the temperature increases the speed of sound also increases, hence in summer the sound travels faster than in winter.

Question 10. Draw a graphical representation of the wave shape for (a) low pitched sound and (b) a high pitched sound.
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound SAQ Q10

Question 11. Give two applications of echo/reflection of sound.
Answer: (i) Ships use reflection of sound technique “SONAR” which helps in locating the depth, distance, direction and speed of underwater objects.
(ii) Ceilings of concert halls are curved so that sound after reflection reaches all comers of the hall.

Question 12. Define amplitude time period and frequency of sound wave.
Answer: Amplitude: The magnitude of the maximum disturbance in the medium on either side of the mean value is called amplitude of the wave. Its unit is meter.
Time Period: The time taken by two consecutive compressions or rarefactions to cross a fixed point is called the time period of the wave.
Frequency: The number of oscillation, occurring per unit time is called the frequency of sound wave.

Question 13. A sound wave causes the density of air at a place to oscillate 1200 times in 2 minutes. Find the time period and frequency of the wave.
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound SAQ Q13

Question 14. Give 3 uses of ultrasound.
Answer: Use of ultrasound:
1. Ultrasound is used to detect cracks and flaws in metal blocks.
2. It is used in ‘echo-cardiography’, the ultrasonic waves are made to reflect from various parts of the heart and form the image of the heart.
3. It is used in ‘ultrasonography’, to detect the image of organs or to detect the abnormalities in the organs. It is also used to examine the foetus during pregnancy to detect congenital defects.

Question: 15. What is the function of middle ear?
Answer: Middle ear consist of three small bones called hammer, anvil and stirrup. These three bones receive the sound vibrations and increase the strength of these vibrations to amplify the vibrations received by ear-drum. These amplified vibrations are furthgr passed to the inner ear.
A ship sends out ultrasound that return from the seabed and is detected after 3.42 s.

Question 16. If the speed of ultrasound through seawater is 1531 m/s. What is the distance of the seabed from the ship?-
Answer: Time between transmission and detection t = 342 s.
Speed of ultrasound in seawater = 1531 m/s.
NCERT Solutions for Class 9 Science Chapter 12 Sound SAQ Q16

Question 17. Distinguish between tone, note and noise.
Answer: Tone: A sound of single frequency is called a tone.
Note: The sound which is produced due to a mixture of several frequencies is called a note.
Noise: The sound which is produced due to a mixture of several frequencies but is unpleasant to the ear is called noise.

Question 18: Establish the relationship between speed, wavelength and frequency of sound.
Answer: Speed of sound —» The distance travelled by a wave or a point on a wave (compression or rarefaction) per unit time.
NCERT Solutions for Class 9 Science Chapter 12 Sound SAQ Q18

Question 19. Which wave property determines
(a) loudness? (b) pitch?
Name the characteristic of the sound which help you to distinguish your friend’s voice while talking in a dark room.
Answer: (a) Loudness is determined by amplitude.
(b) Pitch is determined by frequency.
The quality or timber of sound helps us to distinguish our friend’s voice while talking in a dark room.

Question 20. A sound produces 13 crests and 15 troughs in 3 seconds. When the second crest is produced the first is 2 cm away from the source? Calculate.
(a) the wavelength (b) the frequency (c) the wave speed.
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound SAQ Q20

NCERT Solutions for Class 9 Science Chapter 12 Long Answer Type Questions

Question 1. Sound cannot travel in vacuum. Describe an experiment to demonstrate this.
Answer: Sound is a mechanical wave and needs a material medium to propagate. It cannot travel in vacuum and can be shown by the following experiment.
• Take an electric bell and an airtight glass bell jar. The electric bell is suspended inside the airtight bell jar. Switch ‘ON’ the electric bell.
• Now, connect the bell jar to vacuum pump.
• Pump out the air from the jar, the sound becomes fainter, although the same current passes through the bell.
• Pump out some more air from the jar, a very feeble sound is heard.
• When the air is completely removed from the jar, no sound is heard.
NCERT Solutions for Class 9 Science Chapter 12 Sound LAQ Q1

Question 2. Explain the structure of the human ear with the help of a diagram.
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound LAQ Q2
(a) Outer Ear: Pinna, auditory canal and tympanic membrane.
Pinna: It collects the sound from the surroundings.
Auditory Canal: The sound waves collected passes through this canal.
Tympanic Membrane: It is a thin membrane which receives the vibrations of sound. A compression reaches the eardrum, the pressure on the outside of the membrane increases and pushes the eardrum inward, and moves out when the rarefaction reaches.
(b) Middle Ear: Consists of three small bones called hammer, anvil and stirrup. The vibrations are received by these three bones and the strength of vibrations is increased i.e., the sound is amplified and passed to inner ear.
(c) Inner Ear: It consist of cochlea and auditory nerve.
Chochlea receives the amplified vibrations and convert them into electrical signals. These electrical signals are sent to the brain via the auditory nerve and the brain interprets the signals as sound.

Question 3. Given that sound travels in air at 340 m/sec, find the wavelength of the waves in air produced by 20 kHz sound source. If the same source is put in a water tank, what would be the wavelength of the sound waves in water? (Speed of sound in water = 1480 m/s.)
Answer: 
NCERT Solutions for Class 9 Science Chapter 12 Sound LAQ Q3

Question 4. A child watching Dussehra celebration from a distance sees the effigy of Ravana burst into flames and hears the explosion associated with it 2 sec after that. How far was he from the effigy if the speed of sound in air that night was 335 m/sec?
Answer:
NCERT Solutions for Class 9 Science Chapter 12 Sound LAQ Q4

NCERT Solutions for Class 9 Science Chapter 12 Sound LAQ Q4.1

NCERT Solutions for Class 9 Science Chapter 12 Sound Activity-Based Questions

Question 1. • Take a tuning fork and set it vibrating by striking its prong on a rubber pad. Bring it near your ear.
• Do you hear any sound?
• Touch one of the prongs of the vibrating tuning fork with your finger and share your experience with your friends.
• Now, suspend a table tennis ball or a small plastic ball by a thread from a support. Touch the ball gently with the prong of a vibrating tuning fork.
• Observe what happens and discuss with your friends.
NCERT Solutions for Class 9 Science Chapter 12 Sound Activity Based Q1
Answer: • Yes, we heard sound.
• If we touch the ball with tuning fork set into vibration, the ball gets displaced from its mean position and starts moving.

Question 2. • Fill water in a beaker or a glass up to the brim. Gently touch the water surface with one of the prongs of the vibrating tuning fork.
• Next dip the prongs of the vibrating tuning fork in water. .
• Observe what happens in both the cases.
• Discuss with your friends why this happens.
• Arrange them on a table near a wall.
• Keep a clock near the open end of one of the pipes and try to hear the sound of the clock through the other pipe.
• Adjust the position of the pipes, so that you can best hear the sound of the clock.
• Now, measure the angles of incidence and reflection and see the relationship between the angles.
NCERT Solutions for Class 9 Science Chapter 12 Sound Activity Based Q2
Answer: In both the cases, sound will be produced by the tuning fork which produces ripples. But in case (1) ripples are produced which will move up and down and in case (2) ripples are produced which will move in sideways.

Question 3. • Take a slinky. Ask your friend to hold one end. You hold the other end. Now stretch the slinky and give it a sharp push towards your friend.
• What do you notice? If you move your hand pushing and pulling the slinky alternatively, what will you observe?
• If you mark a dot on the slinky, you’ll observe that the dot on the slinky will move back and forth parallel to the direction of propagation of the disturbance.
NCERT Solutions for Class 9 Science Chapter 12 Sound Activity Based Q3
Answer: When we give a small jerk a hump is produced and this travels forward. When we give a sharp push continuous disturbance is produced. When we give a push or pull to the slinky, slinky starts moving in the forward and backward direction parallel to the direction of propagation of the disturbance.

Question 4. • Take two identical pipes. The length of the pipes should be sufficiently long.
NCERT Solutions for Class 9 Science Chapter 12 Sound Activity Based Q4
• Lift the pipes on the right .vertically to a small height and observe what happens.
Answer: (i) Reflection of sound is similar to reflection of light i.e. Angle of incidence = Angle of reflection.
(ii) If we lift the pipe vertically to a small height, well not be able to hear the sound through the other end of the pipe because Angle of incidence * Angle of reflection. Therefore the reflected ray will not travel through the pipe B.

NCERT Solutions for Class 9 Science Chapter 12 Sound Value-Based Questions

Question 1. Raj noticed that his pet dog was frightened and trying to hide in safe place in his house when some crackers were burst in the neighbourhood. He realized the problem and he decided not to burst crackers during diwali or for any other celebrations.
(a) What must be the range of crackers sound?
(b) Name two diseases that can be caused due to noise pollution.
(c) Name the values of Raj reflected in above act.
Answer: (a) The range of crackers sound must be between 20 Hz to 20 kHz.
(b) Two diseases that can occur due to noise pollution are heart attack and high blood pressure.
(c) Raj reflects the value of respecting sensitivity for animals and caring for animals.

Question 2. It is not advisable to construct houses near airports, in spite of that many new residential apartments are constructed near airports. Sumit files RTI and also complains the municipal office about the same.
(a) Why one should not reside near airport?
(b) Name other two places where there is noise-pollution.
(c) What value of Sumit is reflected in this act?
Answer: (a) The landing and taking off of the air-planes causes lot of noise pollution which may lead to deafness, high blood pressure and other health problems.
(b) The other two places where there is noise-pollution is, residing near the heavy traffic routes and railway stations or lines.
(c) Sumit shows participating citizen and moral responsibility values.

NCERT Solutions for Class 9 Science Chapter 11 Work Power and Energy

NCERT Solutions Class 9 Science Chapter 11 Work, Power And Energy – Here are all the NCERT solutions for Class 9 Science Chapter 11. This solution contains questions, answers, images, step by step explanations of the complete Chapter 11 titled Work, Power And Energy of Science taught in class 9. If you are a student of class 9 who is using NCERT Textbook to study Science, then you must come across Chapter 11 Work, Power And Energy. After you have studied lesson, you must be looking for answers of its questions. Here you can get complete NCERT Solutions for Class 9 Science Chapter 11 Work, Power And Energy in one place. For a better understanding of this chapter, you should also see Chapter 11 Work, Power And Energy Class 9 notes , Science.

Topics and Sub Topics in Class 9 Science Chapter 11 Work Power and Energy:

  1. Work Power and Energy
  2. Work
  3. Energy
  4. Rate of Doing Work

These solutions are part of NCERT Solutions for Class 9 Science. Here we have given Class 9 NCERT Science Textbook Solutions for Chapter 11 Work Power and Energy

NCERT Textbook for Class 9 Science – Page 148
Q1: A force of 7 N acts on an object. The displacement is, say 8 m, in the direction of the force. Let us take it that the force acts on the object through the displacement. What is the work done in this case?
NCERT Solutions for Class 9 Science Chapter 11 Work Power and Energy Page 148 Q1

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Class 9 Science NCERT Textbook – Page 149
Q1. When do we say that work is done?
Work is said to be done when a force causes displacement of an object in the direction of applied force.
Q2. Write an expression for the work done when a force is acting on an object in the direction of its displacement.
Work done = Force x Displacement
Q3. Define 1J of work.
When a force of IN causes a displacement of 1m, in its own direction the work done is said to be one joule.
Q4. A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is done in ploughing the length of the field?
Work done = Force x Displacement = 140 x 15 = 2,100 J

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NCERT Textbook for Class 9 Science – Page 152
Q1. What is the kinetic energy of an object?
The energy possessed by a body by virtue of its motion is called kinetic energy.
Q2. Write an expression for the kinetic energy of an object.
NCERT Solutions for Class 9 Science Chapter 11 Work Power and Energy Page 152 Q2

Q3. The kinetic energy of an object of mass, m moving with a velocity of 5 ms-1 is 25 J. What will be its kinetic energy when its velocity is doubled? What will be its kinetic energy when its velocity is increased three times?
NCERT Solutions for Class 9 Science Chapter 11 Work Power and Energy Page 152 Q3
NCERT Solutions for Class 9 Science Chapter 11 Work Power and Energy Page 152 Q3.1

Class 9 Science NCERT Textbook – Page 156

Q1. What is power?
Power is defined as the rate of doing work
Q2. Define 1 watt of power.
When a work of 1 joule is done in 1 s, the power is said to be one watt.
Q3. A lamp consumes 1000 J of electrical energy in 10 s. What is its power?
Given W = 1000J, t = 10s, P =?
We know, P = W/t = 1000/10 = 100W
Q4. Define average power.
When a machine or person does different amounts of work or uses energy in different intervals of time, the ratio between the total work or energy consumed to the total time is average power.

NCERT Textbook for Class 9 Science – Page 158

Q1. Look at the activities listed below. Reason out whether or not work is done in the light of your understanding of the term ‘work’.
(a) Suma is swimming in a pond.
(b) A donkey is carrying a load on its back.
(c) A wind mill is lifting water from a well.
(d) A green plant is carrying out photosynthesis.
(e) An engine is pulling a train.
(f) Food grains are getting dried in the sun.
(g) A sailboat is moving due to wind energy.
Work is done whenever the given conditions are satisfied:
(i) A force acts on a body.
(ii) There is a displacement of the body.
(a) While swimming, Suma applies a force to push the water backwards. Therefore, Suma swims in the forward direction caused by the forward reaction of water. Here, the force causes a displacement. Hence, work is done by Seema while swimming.
(b) While carrying a load, the donkey has to apply a force in the upward direction. But, displacement of the load is in the forward direction. Since, displacement is perpendicular to force, the work done is zero.
(c) A wind mill works against the gravitational force to lift water. Hence, work is done by the wind mill in lifting water from the well.
(d) In this case, there is no displacement of the leaves of the plant. Therefore, the work done is zero.
(e) An engine applies force to pull the train. This allows the train to move in the direction of force. Therefore, there is a displacement in the train in the same direction. Hence, work is done by the engine on the train.
(f) Food grains do not move in the presence of solar energy. Hence, the work done is zero during the process of food grains getting dried in the Sun.
(g) Wind energy applies a force on the sailboat to push it in the forward direction. Therefore, there is a displacement in the boat in the direction of force. Hence, work is done by wind on the boat.

Q2. An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object?
Since the body returns to a point which is on the same horizontal line through the point of projection, no displacement has taken place against the force of gravity, therefore, no work is done by the force due to gravity.

Q3. A battery lights a bulb. Describe the energy changes involved in the process.
Within the electric cell of the battery the chemical energy changes into electrical energy. The electric
energy on flowing through the filament of the bulb, first changes into heat energy and then into the light energy.

Q4. Certain force acting on a 20 kg mass changes its velocity from 5 m s-1 to 2 m s-1. Calculate the work done by the force.
NCERT Solutions for Class 9 Science Chapter 11 Work Power and Energy Page 158 Q4

Q5. A mass of 10 kg is at a point A on a table. It is moved to a point B. If the line joining A and B is horizontal, what is the work done on the object by the gravitational force? Explain your answer.
The work done is zero. This is because the gravitational force and displacement are perpendicular to each other.

Q6. The potential energy of a freely falling object decreases progressively. Does this violate the law of conservation of energy? Why?
It does not violate the law Of conservation of energy. Whatever, is the decrease in PE due to loss of height, same is the increase in the KE due to increase in velocity of the body.

Q7. What are the various energy transformations that occur when you are riding a bicycle?
The chemical energy of the food changes into heat and then to muscular energy. On paddling, the muscular energy changes into mechanical energy

Q8. Does the transfer of energy take place when you push a huge rock with all your might and fail to move it? Where is the energy you spend going?
Energy transfer does not take place as no displacement takes place in the direction of applied force. The energy spent is used to overcome inertia of rest of the rock.

Q9. A certain household has consumed 250 units of energy during a month. How much energy is this in joules?
NCERT Solutions for Class 9 Science Chapter 11 Work Power and Energy Page 158 Q9

Q10. An object of mass 40 kg is raised to a height of 5 m above the ground. What is its potential energy?
If the object is allowed to fall, find its kinetic energy when it is half-way down.

Q11. What is the work done by the force of gravity on a satellite moving round the earth? Justify your answer.
When a satellite moves round the Earth, then at each point of its path, the direction of force of gravity on the satellite (along the radius) is perpendicular to the direction of its displacement (along the tangent). Hence, the work done on the satellite by the force of gravity is zero.

Q12. Can there be displacement of an object in the absence of any force acting on it? Think. Discuss this question with your friends and teacher.
The answer is both Yes and No. Yes because when an object moves in deep space from one point to another point in a straight line, the displacement takes place, without the application of force. No, because force cannot be zero for displacement on the surface of earth. Some force is essential.

Class 9 Science NCERT Textbook – Page 159

Q13. A person holds a bundle of hay over his head for 30 minutes and gets tired. Has he done some work or not? Justify your answer.
The person does not do work because no displacement takes place in the direction of applied force as the force acts in the vertically upward direction.

Q14. An electric heater is rated 1500 W. How much energy does it use in 10 hours?
Energy consumed by an electric heater can be obtained with the help of the expression,
P=W/t
where,
Power rating of the heater, P = 1500 W = 1.5 kW
Time for which the heater has operated, t = 10 h
Work done = Energy consumed by the heater
Therefore, energy consumed = Power × Time
= 1.5 × 10 = 15 kWh
Hence, the energy consumed by the heater in 10 h is 15 kWh or 15 units.

Q15. Illustrate the law of conservation of energy by discussing the energy changes which occur when we draw a pendulum bob to one side and allow it to oscillate. Why does the bob eventually come to rest? What happens to its energy eventually? Is it a violation of the law of conservation of energy?
When the pendulum bob is pulled (say towards left), the energy supplied is stored in it is the form
Of PE on account of its higher position. When the pendulum is released so that it starts moving towards right, then its PE changes into KE such that in mean position, it has maximum KE, and Zero PE. As the pendulum moves towards extreme right, its KE changes into PE such that at the extreme position, it has maximum PE and zero KE. When it moves from this extreme position to mean position, its PE again changes to KE. This illustrates the law Of conservation of energy. Eventually, the bob comes to rest, because during each oscillation a part of the energy possessed by it transferred to air and in overcoming friction at the point of suspension. Thus, the energy of the pendulum is dissipated in air.
The law of conservation of energy is not violated because the energy merely changes its form and is not destroyed.

Q16. An object of mass, m is moving with a constant velocity, v. How much work should be done on the object in order to bring the object to rest?
Kinetic energy of an object of mass m moving with a velocity v is given by the expression 1/2mv². To bring the object to rest, an equal amount of work i.e. 1/2mv² is required to be done on the object.

Q17. Calculate the work required to be done to stop a car of 1500 kg moving at a velocity of 60 km/h.
NCERT Solutions for Class 9 Science Chapter 11 Work Power and Energy Page 159 Q17

Q18. In each of the following a force, is acting on an object of mass, . The direction of displacement is from west to east shown by the longer arrow. Observe the diagrams carefully and state whether the work done by the force is negative, positive or zero.
NCERT Solutions for Class 9 Science Chapter 11 Work Power and Energy Page 159 Q18
Case I
NCERT Solutions for Class 9 Science Chapter 11 Work Power and Energy Page 159 Q18.1
In this case, the direction of force acting on the block is perpendicular to the direction of displacement. Therefore, work done by force on the block will be zero.
Case II
NCERT Solutions for Class 9 Science Chapter 11 Work Power and Energy Page 159 Q18.2
In this case, the direction of force acting on the block and the direction of displacement is same. Therefore, work done by force on the block will be positive.
Case III
NCERT Solutions for Class 9 Science Chapter 11 Work Power and Energy Page 159 Q18.3
In this case, the direction of force acting on the block is opposite to the direction of displacement. Therefore, work done by force on the block will be negative.

Q19. Soni says that the acceleration in an object could be zero even when several forces are acting on it. Do you agree with her? Why?
Yes, acceleration in an object could be zero even when several forces are acting on it. This happens when all the forces cancel out each other i.e., the net force acting on the object is zero.

Q20. Find the energy in kWh consumed in 10 hours by four devices of power 500 W each.
Power rating of each device, P = 500 W = 0.50 kW
Time for which each device runs, t = 10 h
Work done = Energy consumed by each device (E)
We know, power = Energy consumed / Time
Energy consumed by each device= Power × Time
E = P x t
= 0.50×10 = 5 kWh
Hence, the energy consumed by four devices of power 500 W each in 10 h will be
4 × 5 kWh = 20 kWh = 20 units

Q21. A freely falling object eventually stops on reaching the ground. What happens to its kinetic energy?
As the object hits the hard ground, its kinetic energy gets converted into
(i) heat energy (the object and the ground become slightly warm)
(ii) sound energy (sound is heard when the object hits the ground)
(iii) potential energy of configuration of the body and the ground (the object and the ground get deformed a little bit at the point of collision).

NCERT Solutions for Class 9 Science Chapter 11 Work, Power and Energy (Hindi Medium)

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NCERT Solutions for Class 9 Science Chapter 10 Gravitation

NCERT Solutions Class 9 Science Chapter 10 Gravitation – Here are all the NCERT solutions for Class 9 Science Chapter 10. This solution contains questions, answers, images, step by step explanations of the complete Chapter 10 titled Gravitation of Science taught in class 9. If you are a student of class 9 who is using NCERT Textbook to study Science, then you must come across Chapter 10 Gravitation. After you have studied lesson, you must be looking for answers of its questions. Here you can get complete NCERT Solutions for Class 9 Science Chapter 10 Gravitation in one place. For a better understanding of this chapter, you should also see Chapter 10 Gravitation Class 9 notes , Science.

Topics and Sub Topics in Class 9 Science Chapter 10 Gravitation:

  1. Gravitation
  2. Gravitation
  3. Free Fall
  4. Mass
  5. Weight
  6. Thrust and Pressure
  7. Archimedes’ Principle
  8. Relative Density

These solutions are part of NCERT Solutions for Class 9 Science. Here we have given NCERT Solutions for Class 9 Science Chapter 10 Gravitation.

In – Text Questions Solved

NCERT Textbook for Class 9 Science – Page 141
Questin 1. Why is it difficult to hold a school bag having a strap made of a thin and strong string?
Answer: The force exerted by a thin and strong string is distributed to very less area and hence the force applied due to the bag is more, the pressure exerted on the body by thin straps will be more and hence will be more painful.
As pressure is inversely proportional to area, if the area is reduced pressure
NCERT Solutions for Class 9 Science Chapter 10 Gravitation Intext Questios Page 141 Q1

Questin 2. What do you mean by buoyancy?
Answer: The upward force exerted by any fluid (liquid, gas) on an object is known as upthrust or buoyancy.

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Questin 3. Why does an object float or sink when placed on the surface of water?
Answer: The density of the objects and water decides the floating or sinking of the object in water.
The density of water is 1 gm/cm3.

  • If the density of an object is less than the density of water then the object will float.
  • If the density of an object is more than the density of water then the object will sink.

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Class 9 Science NCERT Textbook – Page 142
Questin 1. You find your mass to be 42 kg on a weighing machine. Is your mass more or less than 42 kg?
Answer: The weighing machine actually measures the weight of the body as the acceleration due to gravity ‘g’ is acting on the body. Hence the mass reading of 42 kg given by a weighing machine is same as the actual mass of the body. As mass is the quantity of inertia, it remains the same.

Questin 2. You have a bag of cotton and an iron bar, each indicating a mass of 100 kg when measured on a weighing machine. In reality, one is heavier than other. Can you say which one is heavier and why?
Answer: The heaviness of the bag can be given by density
NCERT Solutions for Class 9 Science Chapter 10 Gravitation Intext Questios Page 142 Q2
Mass of both cotton bag and iron bag is same. But the volume of cotton bag is more than the iron bag.
Hence density is inversely proportional to volume. The bag of iron will be heavier.

Questions From NCERT Textbook for Class 9 Science

Question 19. In what direction does the buoyant force on an object immersed in a liquid act?
Answer: The buoyant force on an object immersed in a liquid acts upwards, i.e. opposite to the direction of the force exerted by the object.

Question 20. Why does a block of plastic released under water come up to the surface of water?
Answer. The floating or sinking of a body in the water is decided by the density of both the body and water’s buoyant force acting on the body by the liquid.
The density of plastic is less than the water and the buoyant force exerted by water on the plastiq block is greater than the force exerted by plastic on the water.

Questin 21. The volume of 50 g of a substance is 20 cm3. If the density of water is 1 gem 3, will the substance float or sink?
Answer.
NCERT Solutions for Class 9 Science Chapter 10 Gravitation Textbook Questions Q21
As the density of a given substance is more than the density of water. The substance will sink in water.

Question 22. The volume of a 500 g sealed packet is 350 cm3. Will the packet float or sink in water if the density of water is lg cmr3? What will be the mass of the water displaced by this packet?
Answer:
NCERT Solutions for Class 9 Science Chapter 10 Gravitation Textbook Questions Q22

NCERT Solutions for Class 9 Science Chapter 10 Gravitation and Floatation (Hindi Medium)

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More Questions Solved 

NCERT Solutions for Class 9 Science Chapter 10 Multiple Choice Questions

Choose the correct option:

  1. The device used to measure the purity of milk is
    (a) hydrometer (b) lactometer
    (d) hygrometer (d) maltometer
  2. The cork floats while the nail sinks in the water, this is due to
    (a) density of cork is more than nail
    (b) density of nail is more than cork.
    (c) density of cork is less than the density of water.
    (d) density of iron is less than the density of water.
  3. The relative density of silver is 10.8 and the density of water is 1o3 kg/m2. The density of silver is
    (a) 1.8 x 1o4 N/m3  (b) 10.8 x 1o3 N/m3
    (c) 1.8 x 1o4 kg/m3 (d) 10.8 x 1o4 kg/m3
  4. Buoyant force exerted by different fluids on a given body is
    (a) same (b) different
    (c) zero  (d) negligible
  5. Liquid A is denser than liquid B, a body of wood is dipped in both the liquids? The buoyant force experienced by the body in
    (a) liquid A is more (b) liquid B is more
    (c) liquid A is less    (d) none of the above
    Answer. 1 -(b), 2—(c), 3—(b), 4-(b), 5—(a).

NCERT Solutions for Class 9 Science Chapter 10 Very Short Answer Type Questions

Question 1. What is the S.I. unit of thrust?
Answer: Newton.

Question 2. What is the S.I. unit of pressure?
Answer: The S.I. unit of pressure = N/m2 = Pascal.

Question 3. Define thrust.
Answer: The net force exerted by a body in a particular direction is called thrust.

Question 4. Define pressure.
Answer: The force exerted per unit area is called pressure.

Question 5. Why is it easier to swim in sea water than in river water?
Answer: The density of sea water is more due to dissolved salts in it as compared to the density of river water. Hence the buoyant force exerted on the swimmer by the sea water is more which helps in floating and makes swimming easier.

Question 6. Why a truck or a motorbike has much wider tyres?
Answer: The pressure exerted by it can be distributed to more area, and avoid the wear and tear of tyres.

Question 7. Why are knives sharp?
Answer: To increase the pressure, area is reduced,
As pressure ∝ 1/Area hence the pressure or force exerted on a body increases.

Question 8. Why is the wall of dam reservoir thicker at the bottom?
Answer: The pressure of water in dams at the bottom is more, to withstand this pressure the dams have wider walls.

Question 9. Why do nails have pointed tips?
Answer: The force exerted when acts on a smaller area, it exerts larger pressure. So the nails have pointed tips.

Question 10. While swimming why do we feel light?
Answer: The swimmer is exerted by an upward force by water, this phenomenon is called buoyancy and it makes the swimmer feel light.

Question 11. Define density and give its unit.
Answer: The density of a substance is defined as mass per unit volume. Its unit is kg/m3.

Question 12. What is relative density?
Answer: The relative density of a substance is the ratio-of its density to that of water.
NCERT Solutions for Class 9 Science Chapter 10 Gravitation VSAQ Q12

NCERT Solutions for Class 9 Science Chapter 10 Short Answer Type Questions

Question 1. A ship made of iron does not sink but the iron rod sinks in water, why?
Answer: The iron rod sinks due to high density and less buoyant force exerted by the water on it, but in case of ship the surface area is increased, the upthrust experienced by the body is more. So it floats on water

Question 2. Camels can walk easily on desert sand but we are not comfortable walking on the sand. State reason.
Answer: Camels feet are broad and the larger area of the feet reduces the force/ pressure exerted by the body on the sand. But when we have to walk on the same sand, we sink because the pressure exerted by our body is not distributed but is directional.

Question 3. What is lactometer and hydrometer?
Answer: Lactometer is a device used to find the purity of a given sample of milk. Hydrometer is a device used to find the density of liquids.

Question 4. The relative density of silver is 10.8. What does this mean?
Answer: It means that the density of silver is 10.8 times more than that of water. T

Question 5. he relative density of gold is 19.3. The density of water is 103 kg/m3? What is the density of gold in S.I. unit?
Answer:
NCERT Solutions for Class 9 Science Chapter 10 Gravitation SAQ Q5

Question 6. State Archimedes’ principle.
Answer: Archimedes’ principle—When a body is immersed fully or partially in a fluid, it experiences an upward force that is equal to the weight of the fluid displaced by it.
It is used in designing of ships and submarines.

Question 7. Two cork pieces of same size and mass are dipped in two beakers containing water and oil. One cork
floats on water but another sink in oil. Why?
Answer: The cork floats on water because the density of cork is less than the density of water, and another cork sinks in the oil because the density of cork is more than the oil.

Question 8. What are fluids? Why is Archimedes’ principle applicable only for fluids? Give the application of Archimedes’ principle.
Answer: Fluids are the substances which can flow e.g., gases and liquids are fluids. Archimedes’ principle is based on the upward force exerted by fluids on any object immersed in the fluid.
Hence it is applicable only for fluids.
Applications of Archimedes’ principle:

  1. It is used in designing of ship and submarine.
  2. It is used in designing lactometer, used to determine the purity of milk,
  3. To make hydrometers, used to determine the density of liquids.

NCERT Solutions for Class 9 Science Chapter 10 Long Answer Type Questions

Question 1. With the help of an activity prove that the force acting on a smaller area exerts a larger pressure?
Answer: Consider a block of wood kept on a table top. The mass of the wooden block is 5 kg. Its dimension is 40 cm x 20 cm x 10 cm.
Now, we have to find the pressure exerted by the wooden block on the table top by keeping it vertically and horizontally.
NCERT Solutions for Class 9 Science Chapter 10 Gravitation LAQ Q1
∴ The pressure exerted by the box in case (a) is more as compared to the pressure exerted in case (b).
The area is reduced and the pressure exerted is more.
This shows that pressure ∝ 1/area.
Pressure will be larger if the area is reduced.
Application:

  • Nails have pointed tips.
  • Knives have sharp edges.
  • Needles have pointed tips.

NCERT Solutions for Class 9 Science Chapter 10 Activity -Based Questions

Question 1.

  • Take an empty plastic bottle. Close the mouth of the bottle with an airtight stopper. Put it in a bucket filled with water. You see that the bottle floats.
  • Push the bottle into the water. You feel an upward push. Try to push it further down. You will find it difficult to push deeper and deeper. This indicates that water exerts a force on the bottle in the upward direction. The upward force exerted by the water goes on increasing as the bottle is pushed deeper till it is completely immersed.
  • Now, release the bottle. It bounces back to the surface.
  • Does the force due to the gravitational attraction of the earth act on this bottle? If so, why doesn’t the bottle stay immersed in water after it is released? How can you immerse the bottle in water?

Answer: Yes, the bottle is attracted downwards by the earth’s gravitational force. On pushing the bottle with force in the water it does not remain there but comes up because of’the upward force exerted by water on the bottle. This upward force is called upthrust or buoyant force. When the upward force or buoyant force is greater than the downward force ‘g’ the bottle will float. But if downward force is greater than upward force, the bottle will sink. The upward force (buoyant force) acting on the bottle can be reduced by increasing the force on the bottle or by filling the bottle with sand, water etc.
NCERT Solutions for Class 9 Science Chapter 10 Gravitation Activity Based Q1

Question 2.

  • Take a beaker filled with water.
  • Take an iron nail and place it on the surface of the water.
  • Observe what happens.

Answer: The iron nail sinks as the density of nail is more and the downward force exerted on nail is more than the buoyant force.
NCERT Solutions for Class 9 Science Chapter 10 Gravitation Activity Based Q2

Question 3.

  • Take a beaker filled with water.
  • Take a piece of cork and an iron nail of equal mass.
  • Place them on the surface of water.
  • Observe what happens.

Answer: The iron nail sinks as.the density of nail is more and the downward force exerted on nail is more than the buoyant force. The cost floats as the density of cost is less and the buoyant force exerted on it is more than the downward force.

Question 4.

  • Take a piece of stone and tie it to one end of a rubber string or a spring balance.
  • Suspend the stone by holding the balance or the string as shown in the figure (a).
    NCERT Solutions for Class 9 Science Chapter 10 Gravitation Activity Based Q4
  • Note the elongation of the string or the reading on the spring balance due to the weight of the stone.
  • Now, slowly dip the stone in the water in a container as shown in Fig. (b).
  • Observe what happens to the elongation of the string or the reading on the balance.
    Observations :
  • In Fig. (a) the elongation of the string is 6 cm.
  • In Fig. (b) when the stone is dipped in water the length of string reduced to 5 cm.
  • The length of the string in case (b) decreases due to the upward force exerted by water on the stone called as buoyant force.

NCERT Solutions for Class 9 Science Chapter 10 Value-Based Questions

Question 1. A milkman sold his milk in the city and always carried lactometer with him. The customers trusted him and his business flourished.
(a) What is lactometer?
(b) What is the principle of working of lactometer?
(c) What value of milkman is seen in this case?
Answer.
(a) Lactometer is a device that measures the purity of milk.
(b) The principle of lactometer is ‘Archimedes’ principle’. It states that when a body is immersed fully or partially in a fluid, it experiences an upward force that is equal to the weight of the fluid displaced by it.
(c) Milkman is very honest and trustworthy.

Question 2. Reeta was wearing a high heel shoe for a beach party, her friend told her to wear flat shoes as she will be tired soon with high heels and will not feel comfortable,
(a) Why would one feel tired with high heel shoes on beach?
(b) Give the unit of pressure.
(c) What value of Reeta’s friend is seen in the above act?
Answer:
(a) The high heel shoes would exert lot of pressure on the loose sand of beach and will sink more in the soil as compared to flat shoes. Hence large amount of force will be required to walk with heels.
(b) Unit of pressure is Pascal.
(c) Reeta’s friend showed the value of being helpful, concerned and intelligent.

Question 3. In the school fair, there was a game in which one need to find the heaviest ball without holding them in hand. Three balls were given and few disposable glasses were kept. Tarun saw his friend struggling to win the game but he was unable to find the heaviest ball. Tarun helped him by dipping the three balls one by one in the glass’es full of water upto the brim and finally they won the game.
(a) Why did Tarun told his friend to dip the balls one by one in completely filled glass of water?
(b) Name the principle used here.
(c) What value of Tarun is reflected in this case?
Answer:
(d) Tarun wanted to measure the amount of water displaced by each ball when dipped in water.
(b) The principle used is ‘Archimedes’ principle’.
(c) Tarun showed the value of being helpful, kind and intelligent.

NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion

NCERT Solutions Class 9 Science Chapter 9 Force and Laws of Motion – Here are all the NCERT solutions for Class 9 Science Chapter 9. This solution contains questions, answers, images, step by step explanations of the complete Chapter 9 titled Force and Laws of Motion of Science taught in class 9. If you are a student of class 9 who is using NCERT Textbook to study Science, then you must come across Chapter 9 Force and Laws of Motion. After you have studied lesson, you must be looking for answers of its questions. Here you can get complete NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion in one place. For a better understanding of this chapter, you should also see Chapter 9 Force and Laws of Motion Class 9 notes , Science.

Topics and Sub Topics in Class 9 Science Chapter 9 Force and Laws of Motion:

  1. Force and Laws of Motion
  2. Balanced and Unbalanced Forces
  3. First Law of Motion
  4. Inertia and Mass
  5. Second Law of Motion
  6. Third Law of Motion
  7. Conservation of Momentum

These solutions are part of NCERT Solutions for Class 9 Science. Here we have given Class 9 NCERT Science Text book Solutions for Chapter 9 Force and Laws of Motion.

In-Text Questions Solved

NCERT Textbook for Class 9 Science – Page 118
Question 1. Which of the following has more inertia:
(a) a rubber ball and a stone of the same size?
(b) a bicycle and a train?
(c) a five-rupees coin and a one-rupee coin?
Answer:
(a) A stone of the same size
(b) a train
(c) a five-rupees coin
As the mass of an object is a measure of its inertia, objects with more mass have more inertia.

More Resources for CBSE Class 9

Question 2. In the following example, try to identify the number of times the velocity of the ball changes.
“A football player kicks a football to another player of his team who kicks the football towards the goal The goalkeeper of the opposite team collects the football and kicks it towards a player of his own team”.
Also identify the agent supplying the force in each case.
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Intext Questions Page 118 Q2
The velocity of football changed four times.

Formulae Handbook for Class 9 Maths and ScienceEducational Loans in India

Question 3. Explain why some of the leaves may get detached from a tree if we vigorously shake its branch.
Answer: When the tree’s branch is shaken vigorously the branch attain motion but the leaves stay at rest. Due to the inertia of rest, the leaves tend to remain in its position and hence detaches from the tree to fall down.

Question 4. Why do you fall in the forward direction when a moving bus brakes to a stop and fall backwards when it accelerates from rest?
Answer: When a moving bus brakes-to a stop: When the bus is moving, our body is also in motion, but due to sudden brakes, the lower part of our body comes to rest as soon as the bus stops. But the upper part of our body continues to be in motion and hence we fall in forward direction due to inertia of motion.
When the bus accelerates from rest we fall backwards: When the bus’ is stationary our body is at rest but when the bus accelerates, the lower part of our body being in contact with the floor of the bus comes in motion, but the upper part of our body remains at rest due to inertia of rest. Hence we fall in backward direction.

Class 9 Science NCERT Textbook – Page 126-127
Question 1. If action is always equal to the reaction, explain how a horse can pud a cart?
Answer: The third law of motion states that action is always equal to the reaction but they act on two different bodies.
In this case the horse exerts a force on the ground with its feet while walking, the ground exerts an equal and opposite force on the feet of the horse, which enables the horse to move forward and the cart is pulled by the horse.

Question 2. Explain, why is it difficult for a fireman to hold a hose, which ejects a large amount of water at a high velocity.
Answer: The water that is ejected out from the hose in the forward direction comes out with a large momentum and equal amount of momentum is developed in the hose in the opposite direction and hence the hose is pushed backward. It becomes difficult for a fireman to hold a hose which experiences this large momentum.

Question 3. From a rifle of mass 4 kg, a bullet of mass 50 g is fired with an initial velocity of 35 m/s. Calculate the initial recoil velocity of the rifle.
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Intext Questions Page 126 Q3

Question 4. Two objects of masses 100 g and 200 g are moving along the same line and direction with velocities of 2 m/s and 1 m/s respectively.
They collide and after the collision the first object moves at a velocity of 1.67 m./s. Determine the velocity of the second object.
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Intext Questions Page 126 Q4

NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion (Hindi Medium)

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Extra Questions from NCERT Textbook for Class 9 Science

Question 1. An object experiences a net zero external unbalanced force. Is it possible for the object to be travelling with a non-zero velocity? If yes, state the conditions that must be placed on the magnitude and direction of the velocity. If no, provide a reason.
Answer: When an object experiences a net zero external unbalanced force, in accordance with second law of motion its acceleration is zero. If the object was initially in a state of motion, then in accordance with the first law of motion, the object will continue to move in same direction with same speed. It means that the object may be travelling with a non-zero velocity but the magnitude as well as direction of velocity must remain unchanged or constant throughout.

Question 2. When a carpet is beaten with a stick, dust comes out of it. Explain.
Answer: The carpet with dust is in state of rest. When it is beaten with a stick the carpet is set in motion, but the dust particles remain at rest. Due to inertia of rest the dust particles retain their position of rest and falls down due to gravity.

Question 3. Why is it advised to tie any luggage kept on the roof of a bus with a rope?
Answer: In moving vehicle like bus, the motion is not uniform, the speed of vehicle varies and it may apply brake suddenly or takes sudden turn. The luggage will resist any change in its state of rest or motion, due to inertia and this luggage has the tendency to fall sideways, forward or backward.
To avoid the fall of the luggage, it is tied with the rope.

Question 4. A batsman hits a cricket ball which then rolls on a level ground. After covering a short distance, the ball comes to rest. The ball slows to a stop because
(a) the batsman did not hit the ball hard enough.
(b) velocity is proportional to the force exerted on the ball.
(c) there is a force on the ball opposing the motion.
(d) there is no unbalanced force on the ball, so the ball would want to come to rest.
Answer: (c) there is a force 6n the ball opposing the motion.

Question 5. A truck starts from rest and rolls down a hill with a constant acceleration. It travels a distance of 400 m in 20 s. Find its acceleration. Find the force acting on it if its mass is 7 tonnes (Hint : 1 tonne = 1000 kg).
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q5

Question 6. A stone of lkg is thrown with a velocity of 20 ms~1 across the frozen surface of a lake and comes to rest after travelling a distance of 50 m. What is the force of friction between the stone and the ice?
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q6

Question 7. 40000 kg engine pulls a train of 5 wagons, each of 2000 kg, along a horizontal track. If the engine exerts a force of 40000 N and the track offers a friction force of 5000 N, then calculate:
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q7

Question 8. An automobile vehicle has a mass of 1500 kg. What must be the force between the vehicle and road if the vehicle is to be stopped with a negative acceleration of 1.7 ms-2?
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q8

Question 9.What is the momentum of an object of mass m, moving with a velocity v?.
(a) (mv)2           (b) mv2                    (c) 1/2 mv2                   (d) mv
Answer: (d) mv

Question 10.Using a horizontal force of 200 N, we intend to move a wooden cabinet across a floor at a constant velocity. What is the friction force that will be exerted on the cabinet?
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q10
As the wooden cabinet moves across the floor at a constant velocity and the force applied is 200 N. Hence the frictional force that will be exerted on the cabinet will be less than 200 N.

Question 11.Two objects each of mass 1.5 kg, are moving in the same straight line but in opposite directions. The velocity of each object is 2.5 ms-1 before the collision during which they stick together. What will be the velocity of the combined object after collision?
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q11

Question 12. According to the third law of motion when we push on an object, the object pushes back on us with an equal and opposite force. If the object is a massive truck parked along the roadside, it will probably not move. A student justifies this by answering that the two opposite and equal forces cancel each other. Comment on this logic and explain why the truck does not move.
Answer: The mass of truck is too large and hence its inertia is too high. The small force exerted on the truck cannot move it and the truck remains at rest. For the truck to attain motion, an external large amount of unbalanced force need to be exerted on it.

Question 13. A hockey ball of mass 200 g travelling at 10 ms-1 is struck by a hockey stick so as to return it along its original path with a velocity at 5 ms-1. Calculate the change of momentum occurred in the motion of the hockey ball by the force applied by the hockey stick.
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q13

Question 14. A bullet of mass 10 p travelling horizontally with a velocity of 150 m-1 strikes a stationary wooden block and comes to rest in 0.03 s. Calculate the distance of penetration of the bullet into the block. Also calculate the magnitude of the force exerted by the wooden block on the bullet.
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q14

NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q14.1

Question 15. An object of mass 1 kg travelling in a straight line with a velocity of 10 ms-1 collides with, and sticks to, a stationary wooden block of mass 5 kg. Then they both move off together in the same straight line. Calculate the total momentum just before the impact and just after the before the impact and just after the impact. Also, calculate the velocity of the combined object.
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q15

Question 16. An object of mass 100 kg is accelerated uniformly from a velocity of 5 ms-1 to 8 ms-1 in 6 s. Calculate the initial and final momentum of the object. Also, find the magnitude of the force exerted on the object.
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q16

NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q16.1

Question 17. Akhtar, Kiran and Rahul were riding in a motorcar that was moving with a high velocity on an expressway when an insect hit the windshield and got stuck on the windscreen. Akhtar and Kiran started pondering over the situation. Kiran suggested that the insect suffered a greater change in momentum as compared to the change in momentum of the motorcar (because the change in the velocity of insect was much more than that of the motorcar). Akhtar said that since the motorcar was moving with a larger velocity, it exerted a larger force on the insect. And as a result the insect died. Rahul while putting an entirely new explanation said that both the motorcar and the insect experienced the same force and a change in their momentum. Comment on these suggestions.
Answer: Rahul gave the correct reasoning and explanation that both the motorcar and the insect experienced the same force and a change in their momentum. As per the law of conservation of momentum.
When 2 bodies collide:
Initial momentum before collision = Final momentum after collision
mu1+ mu= mv1+ mv2
The equal force is exerted on both the bodies but, because the mass of insect is very small it will suffer greater change in velocity.

Question 18. How much momentum will a dumb-bell of mass 10 kg transfer to the floor if it falls from a height of 80 cm? Take its downward acceleration to be 10 ms-2.
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Extra Questions Q18

Additional Exercises

Question 1. The following is the distance-time table on an object in motion:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Additional Exercises Q1
(a) What conclusion can you draw about the acceleration? Is it constant, increasing, decreasing, or zero?
(b) What do you infer about the forces acting on the object?
Answer: As per given table initial speed of the object is zero. Applying the relation
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Additional Exercises Q1.1

Question 2. Two persons manage to push a motorcar of mass 1200 kg at a uniform velocity along a level road. The same motorcar can be pushed by three persons to produce an acceleration of 0.2 ms-2. With what force does each person push the motorcar? (Assume that all persons push the motorcar with the same muscular effort.)
Answer: Let each person applies a force F on a motorcar of mass, m = 1200 kg.
When two persons push the car, they just manage to move it at a uniform velocity. It means that their combined force 2F is just balanced by force of friction due to road and car moves with a uniform velocity.
When three persons push the car, they apply a total force 3F on the car.
Now net unbalanced force’ on the car = force applied by three persons – frictional force
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Additional Exercises Q2

Question 3. A hammer of mass 500 g, moving at 50 ms-1, strikes a nail. The nail stops the hammer in a very short time of 0.01 s. What is the force of the nail on the hammer?
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Additional Exercises Q3

Question 4. A motorcar of mass 1200 kg is moving along a straight line with a uniform velocity of 90 km/h. Its velocity is slowed down to 18 km/h in 4 s by an unbalanced external force. Calculate the acceleration and change in momentum. Also calculate the magnitude of the force required.
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Additional Exercises Q4
-ve sign of acceleration, charge in momentum and force suggests that the force is opposing the motion of motor car.

Question 5. A large truck and a car, both moving with a velocity of magnitude v, have a head- on collision and both of them come to a halt after that. If the collision lasts for 1 s:
(a) Which vehicle experiences the greater force of impact?
(b) Which vehicle experiences the greater change in momentum?
(c) Which vehicle experiences the greater acceleration?
(d) Why is the car likely to suffer more damage than the truck?
Answer:
(a) During head on collision forces applied by truck and car are action-reaction forces. Hence both vehicles experience same (equal) force of impact.
(b) Here initial velocity of both car and truck is same equal to v and final velocity of both is zero. But mass of truck is much more than that of car, hence change in momentum of truck is more than change in momentum of car.
(c) For same force of impact, the acceleration of car will have greater magnitude because its mass is less.
(d) Car suffers more damage than the truck, as acceleration of car is more, its velocity falls to zero in a shorter time and consequently, its momentum changes in a shorter time.

More Questions Solved

NCERT Solutions for Class 9 Science Chapter 9 Multiple Choice Questions

Choose the correct option:
1. The S.I. unit of force is
(a) kgm/s (b) kgm/s2
(c) Newton ( (d) Newton-meter
2. The product of mass and velocity gives a physical quantity
(a) force (b) inertia
(c) momentum (d) Newton
3. The rate of change of momentum of an object is proportional to
(a) mass of the body (b) velocity of the body
(c) net force applied on the body (d) none of these .
4. If two balls of different masses are dropped on sand, the depths of penetration is same if:
(a) heavier ball is dropped faster than lighter ball
(b) lighter ball is dropped faster than heavier ball
(c) the product ‘mi/ is same for both bodies
(d) none of these
5. The coin remains at rest in the figure shown. This is due to
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion MCQs Q5
(a) inertia of rest
(b) two forces act on the coin which balance each other
(c) no unbalanced force acts on it
(d) all of these
6. A force of 50 N moves a body.
(a) Frictional force exerted on the body is less than 50 N
(b) Frictional force exerted on the body is more than 50 N
(c) None of these
(d) Both (a) and (b)
7. Fielder giving a swing while catching a ball is an example of
(a) inertia (b) momentum
(c) Newton’s II law of motion (d) Newton’s I law of motion
8. Action and reaction forces
(a) acts on same body (b) act on different bodies
(c) act in same direction (d) both (a) and (c)
9. When we stop pedaling the bicycle it stops because
(a) the earths gravitational force acts on it
(b) it is not accelerated
(c) no unbalanced force acts on it
(d) frictional force acts on it
10. A football and a stone has same mass
(a) both have same inertia (b) both have same momentum
(c) both have different inertia (d) both have different momentum
Answer. 1—(c), 2—(c), 3—(c), 4-(c), 5-(d), 6-(a), 7-(c), 8-(b), 9-(d), 10-(a).

NCERT Solutions for Class 9 Science Chapter 9 Very Short Answer Type Questions

Question 1. Define force.
Answer: It is a push or pull on an object that produces acceleration in the body on which it acts. 4

Question 2. What is S.I. unit of force?
Answer: S.I. unit of force is Newton.

Question 3. Define one Newton.
Answer: A force of one Newton produces an acceleration of 1 m/s2 on an object of mass 1 kg. .
1 N = 1 kg m/s2

Question 4. What is balanced force?
Answer: When forces acting on a body from the opposite direction do not change the state of rest or of motion of an object, such forces are called balanced forces.

Question 5. What is frictional force?
Answer: The force that always opposes the motion of object is called force of friction.

Question 6. What is inertia?
Answer: The natural tendency of an object to resist a change in their state of rest or of uniform motion is called inertia.

Question 7. State Newton’s first law of motion.
Answer: An object remains in a state of rest or of uniform motion in a straight line unless acted upon by an external unbalanced force.

Question 8. State Newton’s second law of motion.
Answer: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the force.

Question 9. What is momentum?
Answer: The momentum of an object is the product of its mass and velocity and has the same direction as that of the velocity. The S. I. unit is kg m/s. (p = mv)

Question 10. State Newton’s III law of motion.
Answer: To every action, there is an equal and opposite reaction and they act on two different bodies.

Question 11. Which will have more inertia a body of mass 10 kg or a body of mass 20 kg?
Answer: A body of mass 20 kg will have more inertia.

Question 12. Name the factor on which the inertia of the body depends.
Answer: Inertia of a body depends upon the mass of the body.

Question 13. Name two factors which determine the momentum of a body.
Answer: Two factors on which momentum of a body depend is mass and velocity. Momentum is directly proportional to the mass and velocity of the body.

Question 14. What decides the rate of change of momentum of an object?
Answer: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of force.

Question 15. The diagram shows a moving truck. Forces A, B,
C and D are acting on the truck.
Name the type of forces acting on a truck.
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion VSAQ Q15
Answer: The forces A, B, C and D acting on the truck are:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion VSAQ Q15.1

NCERT Solutions for Class 9 Science Chapter 9 Short Answer Type Questions

Question 1. State the difference in balanced and unbalanced force.
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion SAQ Q1

Question 2. What change will force bring in a body?
Answer: Force can bring following changes in the body:

  1. It can change the speed of a body.
  2. It can change the direction of motion of a body,
  3. It can change the shape of the body.

Question 3. When a motorcar makes a sharp turn at a high speed, we tend to get thrown to one side. Explain why?
Answer: It is due to law of inertia. When we are sitting in car moving in straight line, we tend to continue in our straight-line motion. But when an unbalanced force is applied by the engine to change the direction of motion of the motorcar. We slip to one side of the seat due to the inertia of our body.

Question 4. Explain why it is dangerous to jump out of a moving bus.
Answer: While moving in a bus our body is in motion. On jumping out of a moving bus our feet touches the ground and come to rest. While the upper part of our body stays in motion and moves forward due to inertia of motion and hence we can fall in forward direction.
Hence, to avoid this we need to run forward in the direction of bus.

Question 5. Why do fielders pull their hand gradually with the moving ball while holding a catch?
Answer: While catching a. fast moving cricket ball, a fielder on the ground gradually pulls his hands backwards with the moving ball. This is done so that the fielder increases the time during which the high velocity of the moving ball decreases to zero. Thus, the acceleration of the ball is decreased and therefore the impact of catching the fast moving ball is reduced.

Question 6. In a high jump athletic event, why are athletes made to fall either on a cushioned bed or on a sand bed?
Answer: In a high jump athletic event, athletes are made to fall either on a cushioned bed or on a sand bed so as to increase the time of the athlete’s fall to stop after making the jump. This decreases the rate of change of momentum and hence the force.

Question 7. How does a karate player breaks a slab of ice with a single blow?
Answer: A karate player applied the blow with large velocity in a very short interval of time on the ice slab which therefore exerts large amount of force on it and suddenly breaks the ice slab.

Question 8. What is law of conservation of momentum?
Answer: Momentum of two bodies before collision is equal to the momentum after collision.
In an isolated system, the total momentum remain conserved.

Question 9. Why are roads on mountains inclined inwards at turns?
Answer: A vehicle moving on mountains is in the inertia of motion. At a sudden turn there is a tendency of vehicle to fall off the road due to sudden change in the line of motion hence the roads are inclined inwards so that the vehicle does not fall down the mountain.

Question 10. For an athletic races why do athletes have a special posture with their right foot resting on a solid supporter?
Answer: Athletes have to run the heats and they rest their foot on a solid supports before start so that during the start of the race the athlete pushes the support with lot of force and this support gives him equal and opposite push to start the race and get a good start to compete for the race.

Question 11.Why do you think it is necessary to fasten your seat belts while travelling in your vehicle?
Or
How are safety belts helpful in preventing any accidents?
Answer: While we are travelling in a moving car, our body remains in the state of rest with respect to the seat. But when driver applies sudden breaks or stops the car our body tends to continue in the same state of motion because of its inertia. Therefore, this sudden break may cause injury to us by impact or collision. Hence, safety belt exerts a force on our body to make the forward motion slower.

Question 12. Explain how momentum gets conserved in collision of two bodies.
Answer: Consider two bodies i.e., balls A and B, the mass and initial velocities are mAuA and mBuB respectively before collision. The two bodies collide and force is exerted by each body. There is change in their velocities due to collision.
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion SAQ Q12
∴ The total momentum of the two balls remains unchanged or conserved provided no other external force acts.

Question 13. When you kick a football it flies away but when you kick a stone you get huh why?
Answer: This is because stone is heavier than football and heavier objects offer larger inertia.
When we kick a football its mass is less and inertia is also less so force applied by our kick acts on it and hence it shows larger displacement but in case of stone, it has larger mass and offers larger inertia. When we kick (action) the stone it exerts an equal and opposite force (reaction) and hence it hurts the foot.

Question 14. If a person jumps from a height on a concrete surface he gets hurt. Explain.
Answer: When a person jumps from a height he is in state of inertia of motion. When he suddenly touches the ground he comes to rest in a very short time and hence the force exerted by the hard concrete surface on his body is very high, and the person gets hurt.

Question 15. What is the relation between Newton’s three laws of motion?
Answer: Newton’s first law explains about the unbalanced force required to bring change in the position of the body.
Second law states/explains about the amount of force required to produce a given acceleration.
And Newton’s third law explains how these forces acting on a body are interrelated.

Question 16. Give any three examples in daily life which are based on Newton’s third law of motion.
Answer: Three examples based on Newton’s third law are :

  1. Swimming: We push the water backward to move forward.
    action – water is pushed behind
    reaction – water pushes the swimmer ahead
  2. Firing gun: A bullet fired from a gun and the gun recoils.
    action – gun exerts force on the bullet
    reaction – bullet exerts an equal and opposite force on the gun
  3. Launching of rocket
    action – hot gases from the rocket are released reaction – the gases exert upward push to the rocket

Question 17. A bullet of m.ass 20 g is horizontally fired with a velocity 150 m/s from a pistol of mass 2 kg. What is the
recoil velocity of the pistol?
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion SAQ Q17

Question 18. Negative sign indicates that the direction in which the pistol would recoil is opposite to that of bullet.
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion SAQ Q18
Two bodies as shown in the figure collide with each other and join thereafter. With what velocity will they move after combining together?
Answer:
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion SAQ Q18.1

NCERT Solutions for Class 9 Science Chapter 9 Long Answer Type Questions

Question 1. Explain Newton’s second law of motion and with the help of an example show how it is used in sports.
Answer: Newton’s second law of motion: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the force.
Let us assume:
Object of mass m, is moving along a straight line with an initial velocity ‘u’, It is uniformly accelerated to velocity v in time ‘t by the application of force,
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion LAQ Q1
In cricket field, the fielder gradually pulls his hands backward while catching a ball. The fielder catches the ball and gives swing to his hand to increase the time during which the high velocity of the moving ball decreases to zero.
The acceleration of the ball is decreased and therefore the impact of catching the fast moving ball4s reduced.
If not done so, then the fast moving ball will exert large force and may hurt the fielder.

Question 2. State all 3 Newton’s law of motion. Explain inertia and momentum.
Answer:
Newton’s I law of motion: An object remains in a state of rest or of uniform motion in a straight line unless acted upon by an external unbalanced force.
Newton’s II law of motion: The rate of change of momentum of an object is proportional to the applied unbalanced force in the direction of the-force.
Newton’s III law of motion: To every action, there is an equal and opposite reaction and they act on two different bodies.
Inertia: The natural tendency of an object to resist a change in their state of rest or of uniform motion is called inertia.
Momentum: The momentum of an object is the product of its mass and velocity and has the same direction as that of the velocity. Its S.I. unit is kgm/s. p = m x v

Question 3. Define force. Give its unit and define it. What are different types forces?
Answer: Force: It is a push or pull on an object that produces acceleration in the body on which it acts.
A force can do 3 things on a body
(a) It can change the speed of a body.
(b) It can change the direction of motion of a body.
(c) It can change the shape of the body.
The S.I. unit of force is Newton.
Newton: A force of one Newton produces an acceleration of 1 m/s2 on an object of mass 1 kg.
1N = 1kg m/s2
Types of forces:

  1. Balanced force: When the forces acting on a body from the opposite direction do not change the state of rest or of motion of an object, such forces are called balanced forces.
  2. Unbalanced force: When two opposite forces acting on a body move a body in the direction of the greater force or change the state of rest, such forces are called as unbalanced force.
  3. Frictional force: The force that always opposes the motion of object is called force of friction.

Question 4. What is inertia? Explain different types of inertia. Give 3 examples in daily life which shows inertia.
Answer:
Inertia: The natural tendency of an object to resist change in their state of rest or of motion is called inertia.
The mass of an object is a measure of its inertia. Its S.I. unit is kg.
Types of inertia:
Inertia of rest: The object at rest will continue to remain at rest unless acted upon by an external unbalanced force.
Inertia of motion: The object in the state of uniform motion will continue to remain in motion with same speed and direction unless it is acted upon by an external unbalanced force. .
Three examples of inertia in daily life are:

  1. When we are travelling in a vehicle and sudden brakes are .applied we tend to fall forward.
  2. When we shake the branch of a tree vigorously, leaves fall down.
  3. If we want to remove the dust from carpet we beat the carpet so that dust fall down.

NCERT Solutions for Class 9 Science Chapter 9 Activity-Based Questions

Question 1.

  • Make a pile of similar carom coins on a table, as shown in the figure.
  • Attempt a sharp horizontal hit at the bottom of the pile using another carom coin or striker. If the hit is strong enough the bottom coin moves out quickly. Once the lowest coin is removed, the inertia of the other coins makes them ‘fall’ vertically on the table.
    Inertia: It is the tendency of a body to maintain its state of rest or of motion.
    NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Activity Based Q1

Question 2.

  • Set a five-rupees coin on a stiff card covering an empty glass tumbler standing on a table as shown in the figure.
  • Give the card a sharp horizontal flick with a finger. If we do it fast then the card shoots away, allowing the coin to fall vertically into the glass tumbler due to its inertia.
  • NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Activity Based Q2

Answer: The force applied on the card due to flicking changes the inertia of the card but the coin resist a change and stay at the rest i.e. inertia of rest and due to gravity falls down in the tumbler.

Question 3.

  • Place a water-filled tumbler on a tray.
  • Hold the tray and turn around as fast as you can.
  • We observe that the water spills. Why?

Answer: The water-filled in tumbler and tray are at rest. On moving/turning around the tray at faster speed the water spills because the tray and the tumbler comes into motion while the water in the tumbler remain at inertia of rest.

Question 4.

  • Request two children to stand on two separate carts as shown on the next page.
  • Give them a bag full of sand or some other heavy object. Ask them to play a game of catch with the bag.
  • Does each of them receive an instantaneous reaction as a result of throwing the sand bag (action)?
  • You can paint a white line on cartwheels to observe the motion of the two carts when the children throw the bag towards each other.

Answer. Yes, in this case each of them receives an instantaneous reaction as a result of throwing the sand bag.
This activity explain Newton’s III law of motion i.e., the force is exerted forward in throwing the bag full of sand and the person who is throwing it gets pushed backward.
NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Activity Based Q4

Question 5.

  • Take a big rubber balloon and inflate it fully. Tie its neck using a thread. Also using adhesive tape, fix a straw on the surface of this balloon.
  • Pass a thread through the straw and hold one end of the thread in your hand or fix it on the wall.
  • Ask your friend to hold the other end of the thread or fix it on a wall at some distance. The arrangement is shown in the figure below.
  • Now remove the thread tied on the neck of balloon. Let the air escape from the mouth of the balloon.
  • Observe the direction in which the straw moves.
    NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Activity Based Q5
    Observation:
    When the air escapes out from the balloon the straw moves in the opposite direction of the air moved out of the balloon.
    This activity explains the law of conservation of momentum and Newton’s III law of motion.
    Initial momentum = Final momentum

Question 6.

  • Take a test tube of good quality glass material and put a small amount of water in it. Place a stop cork at the mouth of it.
  • Now suspend the test tube horizontally by two strings or wires as shown in the figure on next page.
  • Heat the test tube with a burner until water vaporises and the cork blows out.
  • Observe that the test tube recoils in the direction opposite to the direction of the cork.
    NCERT Solutions for Class 9 Science Chapter 9 Force and Laws of Motion Activity Based Q6
    Observation:
    The cork is pushed out in forward direction by the hot steam. The test tube is pushed in the backward direction.
    It explain Newton’s III law of motion and conservation of momentum.

NCERT Solutions for Class 9 Science Chapter 9 Value-Based Questions

Question 1. Class V students were playing cricket with the cork hall in the school campus. Charu a senior student told them about the accidents that can occur due to cork ball in the campus and also advised them to bring soft cosco ball to play the game.
(a) Why it was safe to play with soft ball and not with hard cork ball?
(b) A player pulls his hands backwards after holding the ball shot at high speed. Why?
(c) What value of Charu is seen in this act?
Answer:
(a) The soft ball will have less inertia as compared to the heavy ball and it would not hurt the players.
(b) By pulling the hand backwards it reduces the force exerted by the ball on hands.
(c) Charu showed the value of being responsible and helpful by nature.

Question 2. Saksham saw his karate expert friend breaking a slate. He tried to break the slate but Saksham’s friend stopped him from doing so and told him that it would hurt, one needs lot of practice in doing so.
(a) How can a karate expert break the slate without any injury to his hand?
(b) What is Newton’s third law of motion?
(c) What value of Saksham’s friend, is seen in the above case?
Answer:
(a) A karate player applies the blow with large velocity in a very short interval of time on the slate, therefore large force is exerted on the slate and it breaks.
(b) To every action there is an equal and opposite reaction, both act on different bodies.
Saksham’s friend showed the value of being responsible and caring friend.

NCERT Solutions for Class 9 Science Chapter 8 Motion

NCERT Solutions Class 9 Science Chapter 8 Motion – Here are all the NCERT solutions for Class 9 Science Chapter 8. This solution contains questions, answers, images, step by step explanations of the complete Chapter 8 titled Motion of Science taught in class 9. If you are a student of class 9 who is using NCERT Textbook to study Science, then you must come across Chapter 8 Motion. After you have studied lesson, you must be looking for answers of its questions. Here you can get complete NCERT Solutions for Class 9 Science Chapter 8 Motion in one place. For a better understanding of this chapter, you should also see Chapter 8 Motion Class 9 notes , Science.

NCERT Solutions for Class 9 Science Chapter 8 Motion

Topics and Sub Topics in Class 9 Science Chapter 8 Motion:

  1. Motion
  2. Describing Motion
  3. Measuring the Rate of Motion
  4. Rate of Change of Velocity
  5. Graphical Representation of Motion
  6. Equations of Motion by Graphical Method
  7. Uniform Circular Motion

These solutions are part of NCERT Solutions for Class 9 Science. Here we have given NCERT Solutions for Class 9 Science Chapter 8 Motion.

Formulae Handbook for Class 9 Maths and ScienceEducational Loans in India

NCERT Solutions for Class 9 Science Chapter 8 Motion 1
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NCERT Solutions for Class 9 Science Chapter 8 Motion (Hindi Medium)

NCERT Solutions for Class 9 Science Chapter 8 Motion Hindi Medium 1
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More Resources for CBSE Class 9

NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms

NCERT Solutions Class 9 Science Chapter 7 Diversity in Living Organisms – Here are all the NCERT solutions for Class 9 Science Chapter 7. This solution contains questions, answers, images, step by step explanations of the complete Chapter 7 titled Diversity in Living Organisms of Science taught in class 9. If you are a student of class 9 who is using NCERT Textbook to study Science, then you must come across Chapter 7 Diversity in Living Organisms. After you have studied lesson, you must be looking for answers of its questions. Here you can get complete NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms in one place. For a better understanding of this chapter, you should also see Chapter 7 Diversity in Living Organisms Class 9 notes , Science.

Topics and Sub Topics in Class 9 Science Chapter 7 Diversity in Living Organisms:

  1. Diversity in Living Organisms
  2. What is the Basis of Classification?
  3. Classification and Evolution
  4. The Hierarchy of Classification- Groups
  5. Plantae
  6. Animalia
  7. Nomenclature

These solutions are part of NCERT Solutions for Class 9 Science. Here we have given Class 9 NCERT Science Textbook Solutions for Chapter 7 Diversity in Living Organisms.

In-Text Questions Solved

NCERT Textbook for Class 9 Science – Page 80
Question 1. Why do we classify organisms?
Answer: For easier and convenient study we classify organisms.

Question 2. Give three examples of the range of variations that you see in life-forms around you.
Answer:
(a) Small cat and big cow
(b) Grass and banyan tree
(c) Black crow and green parrot

More Resources for CBSE Class 9

CBSE Class 9 Science NCERT Textbook – Page 82
Question 1. Which do you think is a more- basic characteristic for classifying organisms?
(a) the place where they live.
(b) the kind of cells they are made of. Why?
Answer: Classification based on living place is more basic as there can be wide variations in organisms living in a given place.

Question 2. What is the primary characteristic on which the first division of organisms is made?
Answer: Nature of cell is the primary characteristics on which the first division of organisms is decided. Based on this criterion life forms can be classified into prokaryotes or eukaryotes.

Formulae Handbook for Class 9 Maths and ScienceEducational Loans in India

Question 3. On what bases are plants and animal’ out into different categories?
Answer: Mode of nutrition and presence or absence of cell walls.

CBSE Class 9 Science NCERT Textbook – Page 83
Question 1. Which organisms are called primitive and how are they different from the so-called – advanced organisms?
Answer: Organisms with simple cellular structure and no division of labour are called
primitive.
Advanced organisms, like mammals have millions of cells and there are different organs and organ system for different biological functions.

Question 2. Will adiKznced organisms be the same as complex organisms? Why? t
Answer: Yes, advanced organisms means greater degree of evolution which leads to more complexity.

CBSE Class 9 Science Ncert textbook Page 85
Question 1. Whaf is the criterion for classification of organisms as belonging to kingdom Monera or Protista?
Answer: It is the presence or absence of a well defined nucleus. Monera has no nuclear membrane, while Protista shows well defined nucleus.

Question 2. In which kingdom will you place an organism which is single-celled, eukaryotic and
photosynthetic?
Answer: Protista.

Question 3. In the hierarchy of classification, which grouping will have the smallest number of organisms with a maximum of characteristics in common and which will have the largest number of organisms?
Answer: Organisms belonging to Kingdom Monera will have the small number of organisms with a maximum of characteristics in common. And kingdom Animalia will have the largest number of organisms.

NCERT Textbook for Class 9 Science – Page 88
Question 1. Which division among plants has the simplest organisms?
Answer: Thallophyta or algae.

Question 2. How are pteridophytes different from the phanerogams?
Answer: Pteridophytes have naked embryo and inconspicuous reproductive organ whereas — phanerogams have well-differentiated reproductive organs and covered embryo.

Question 3. How do gymnosperms and angiosperms differ from each other?
Answer: Seeds are naked in Gymnosperms and are covered in angiosperms.

NCERT Textbook for Class 9 Science – Page 94
Question 1. How do poriferan animals differ from coelenterate animals?
Answer:

  • Animals from Porifera show cellular level of organisation, while those from Coelenterata show tissue level of organisation.
  • In Porifera there is no division of labour, while in Coelenterata some division of labour is seen.
  • Porifera do not have coelom, while coelenterata have coelom.

Question 2. How do annelid animals differ from arthropods?
Answer:
NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms Intext Questions Page 94 Q2

Question 3. What are the differences between amphibians and reptiles?
Answer:
NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms Intext Questions Page 94 Q3

Question 4. What are the differences between animals belonging to the Aves group and those in the mammalia group?
Answer:
NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms Intext Questions Page 94 Q4

Extra Questions for CBSE Class 9 Science (Biology) Diversity in Living Organisms

Question 1. What are the advantages of classifying organisms?
Answer: Advantages of classification:

  • Better categorization of living beings based on common characters.
  • Easier study for scientific research.
  • Better understanding of human’s relation and dependency on other organisms.
  • Helps in cross breeding and genetic engineering for commercial purposes.

Question 2. How would you choose between two characteristics to be used for developing a hierarchy  in classification?
Answer: Gross Character will “form-the basis of start of the hierarchy and fine character -will -form “the basis of further steps of single the hierarchy.
Example:

  1. Presence of vertebral column in human beings can be taken under vertebrata.
  2. Presence of four limbs makes them members of Tetrapoda.
  3. Presence of mammary glands keeps them under mammalia.

Question 3. Explain the basis for grouping organisms into five kingdoms.
Answer: Basis Of Clasiffication:
(a) Number of cells
(b) Layer of cells
(c) Presence or absence of cell wall
(d) Mode of nutrition
(e) Level Of organization

Question 4. What are the major divisions in the Plantae? What is the basis for these divisions?
Answer: Major Divisions of Kingdom plantea:

DivisionBasis of Classification
Thallophyta or AlgaeThallus like body
BryophytaBody is divided into leaf and stem
PteridophytaBody is divided into root, stem and leaf
GymnospermSeed bearing, naked seeds
AngiospermSeed bearings covered seeds

Question 5. How are the criteria for deciding divisions in plants different from the criteria for deciding the subgroups among animals?
Answer: In plants body basic structure is a major criteria based on which Thallophytes are different from Bryophytes. Apart from this absence or presence of seeds is another important criteria. Gymnosperms and angiosperms are further segregated based on if seeds are covered or not. It is clear that it is the morphological character which makes the basis for classification of plants.
In animals classification is based on more minute structural variations. So in place of morphology, cytology forms the basis. Animals are classified based on layers of cells, presence or absence of coelom. Further higher the hierarchy animals are classified based on presence or absence of smaller features, like presence or absence of four legs.

Question 6. Explain how animals in Vertebrata are classified into further subgroups.
Answer: Vertebrata is divided into two superclasses, viz. Pisces and Tetrapoda. Animals of Pisces have streamlined body with fins and tails to assist in swimming. Animals of Tetrapoda have four limbs for locomotion.
Tetrapoda is further classified into following classes:
(a) Amphibia: Are adapted to live in water and on land. Can breathe oxygen through skin when under water.
(b) Reptilia: These sire crawling animals. Skin is hard to withstand extreme temperatures.
(c) Aves: Forelimbs are modified into wings to assist in flying. Beaks are present. Body is covered with feathers.
(d) Mammalia: Mammary glands present to nurture young ones. Skin is covered with hair. Most of the animals are viviparous.

NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms (Hindi Medium)

NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms Hindi Medium 1
NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms Hindi Medium 2
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NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms Hindi Medium 7
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NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms Hindi Medium 11
NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms Hindi Medium 12
NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms Hindi Medium 13
NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms Hindi Medium 14

More Questions Solved

NCERT Solutions for Class 9 Science Chapter 7 Very Short Answer Questions

Question 1. Who wrote the book “The Origin of Species”?
Answer: Charles Darwin in 1859.

Question 2. Who proposed the classification of organisms into 5 kingdom?
Answer: Robert Whittaker (1959).

Question 3. Define species.
Answer: All organisms that <are similar to breed and perpetuate.

Question 4. Give example of the organism belonging to Monera and Protista Kingdom.
Answer: Monera—Anabaena, blue-gr^en algae Protista—Eugleno, Paramecium, Amoeba

Question 5. Name the appendages used for movement by organism belonging to Protista kingdom
Answer:
Paramecium – Cilia
Euglena – Flagella
Amoeba – Pseudopodia

Question 6. What is lichen?
Answer: The symbiotic association of fungi and blue-green algae, is called lichen.

Question 7. What is symbiotic relationship?
Answer: It is a relationship between two organisms in which both of them are benefitted, e.g., fungi gets food from blue-green algae and in return blue-green gets shelter [lichens].

Question 8. What is saprophytic nutrition?
Answer: The organisms using dead and decaying organic matter as food are said to show saprophytic nutrition.

Question 9. Give simple dassificatian of plant kingdom.
Answer:
NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms VSAQ Q9

Question 10. Name the plant amphibian.
Answer: Biyophyta e.g. Funaria (Moss).

Question 11. What are cryptogamae?
Answer: The plants with inconspicuous reproductive organs are called cryptogamae, e.g., fern.

Question 12. Give examples of pteridophyte.
Answer: Marsilea and Fern.

Question 13. Name the reproductive organ of plants.
Answer: Flower.

Question 14. What are gymnosperms?
Answer: The group of plants that bear naked seeds e.g., pines, deodar.

Question 15. What are angiosperms?
Answer: The group of plants with covered seeds are called angiosperms. These are flowering plants.

Question 16. What are cotyledons?
Answer: Plant embryos in seeds have structures called cotyledons. Cotyledens are also known as seed leaves.

Question 17. Name the phylum of an animals with pores on it.
Answer: Porifera e.g., sponge.

Question 18. Name the phylum of Jellyfish
Answer: Coelenterata or Cnidaria.

Question 19. What is the meaning of triploblastic?
Answer: Animals which have three layers of cells from which differentiated tissues -can be made.

Question 20. What is bilateral symmetry?
Answer: When the left and right halves of the body have same design it is called bilateral symmetry.

Question 21. What is the meaning of “cold-blooded animal”?
Answer: Those animals who show the variation in their body temperature according to the surroundings are called cold-blooded animals, e.g., fish, amphibians, reptiles.

Question 22. Name two mammals that lay eggs.
Answer: Platypus and echidna.

Question 23. Name three mammals that live in water.
Answer: Whale, platypus and Dolphins.

Question 24. Name a fish with skeleton made up of cartilage.
Answer: Shark.

Question 25. Name two fish which have skeleton made up of both bone and cartilage.
Answer: Tuna and rohu.

Question 26. Name the reptile with four-chambered heart.
Answer: Crocodile.

NCERT Solutions for Class 9 Science Chapter 7 Short Answer Type Questions

Question 1. Give the characteristics of Monera.
Answer:
(a) Organisms are unicellular, do not have a defined nucleus.
(b) Organisms may have a cell wall or may not have cell wall.
(c) Mode of nutrition is either autotrophic or heterotrophic.

Question 2. Give the characteristics of Protista.
Answer:
(a) Organsims are unicellular and eukaryotic.
(b) Use appendages for locomotion like cilia, flagella, etc.
(c) Nutrition is either autotrophic or heterotrophic.
(d) E.g., algae, protozoa.

Question 3. Give the difference between thallophyta and bryophyta.
Answer:

ThallophytaBryophyta
Body is thallus like not differentiated into -root, stem. Example: Spirogyra.Plant Body is differentiated into stem and leaf like structures. Example: Moss.

Question 4. What are hermaphrodites? Give two examples.
Answer: When an organism has both the sexes, i.e., it can produce both sperms and eggs are called hermaphrodites. Example: Sponges, earthworms.

Question 5. Give the difference between monocots and dicots.
Answer:

MonocotsDicots
1. Seeds with one cotyledon. 2. Leaves have parallel venation. 3. Root system—fibrous.Seeds with two cotyledons. Leaves have reticulate venation. Root system—tap root.

Question 6. Give the difference between two types of symmetry that animals show.
Answer: Symmetry—Bilateral and Radial

Bilateral SymmetryRadial Symmetry
Any organism that has same design on left and right halves of the body. Example: Earthworm, spider, cockroach.Any organisms with a body design such that it can be divided into two equal halves from any radius. Example: Starfish sea urchin.

Question 7. Differentiate between vertebrates and invertebrates.
Answer:

VertebratesInvertebrates
1. Notochord is present. 2. True internal skeleton present.Notochord is absent. No true internal skeleton present.

Question 8. Name the phylum of the following animals:
(a) Tapeworm (b) Starfish
(c) Jellyfish     (d) Octopus
Answer:
(a) Tapeworm – Flatyhelminthes
(b) Starfish – Echinodermatai
(c) Jellyfish – Coelenterata
(d) Octopus – Mollusca

Question 9. Identify the phylum for the following characteristics given:
(a) Organisms with joint appendages.
(b) Organisms are generally flat worms.
(c) Body is segmented.
(d) Skin of organisms is full of spikes.
Answer:
(a) Arthropoda
(b) Platyhelminthes
(c) Ann elida
(d) Echinodermata

Question 10. State the features of all chordates.
Answer: All chrodates  possess the following features:

  1. Have a notochord
  2. Have a dorsal nerve chord
  3. Are triploblastic
  4. Have paired gill pouches

Question 11. Give general characteristics of Porifera.
Answer:
(a) Animals with pores all over the body.
(b) Body is not well differentiated.
(c) Non-motile animals, remain attached to solid support.
(d) Body is covered with hard outer skeleton. Example, sponges.

Question 12. How are pores or holes all over the body of Porifera important?
Answer: The pores or holes present all over the body of the organisms lead to a canal system that helps in circulating water throughout the body to bring in food and oxygen.

Question 13. Give general characteristics of ‘Platyhelminthes’?
Answer:
(a) These are flat worms.
(b) Most of them are parasites.
(c) Animals are triploblastic
(d) No true internal body cavity.
E.g., Tapeworm, planaria, Liver fluke.

Question 14. Give specific characteristics of Coelenterata.
Answer:
(a) Water living animals.
(b) Body is made of two layers of cells.
(c) Some of them live in colonies (corals), while others have solitary life-span {Hydra).
(d) Body cavity present.

Question 15. Give the characteristics of Arthropoda with 2 examples.
Answer:
(a) Arthropoda means jointed legs’.
(b) Animals are bilaterally symmetrical and segmented.
(c) It has an open circulatory system.
(d) This is the largest group of animals.
Example: Spider, scorpionts, crabs, house flies.

Question 16. Give the characteristic features of Echinodermata.
Answer:
(a) Spikes present on skin.
(b) Free living, marine animals.
(c) Triploblastic and have a coelomic cavity.
(d) Have a peculiar water driven tube system used for moving around.
(e) Have hard calcium carbonate structure that is used as a skeleton.
Example, Starfish, seaurchin.

Question 17. Give the characteristics of mammals.
Answer:
(a) Mammals are warm-blooded animals.
(b) Four-chambered heart.
(c) Mammary glands for production of milk to nourish their younger one.
(d) Skin has hairs, sweat glands and oil glands.
(e) Most of them produce their young ones (viviparous).

Question 18. What are the conventions followed for writing the scientific names?
Answer: The conventions followed while writing the scientific names are:
1. The name of the genus begins with a capital letter.
2. The name of the species begins with a small letter.
3. When printed, the scientific name is given in italics.
4. When written by hand, the genus name and the species name have to be underlined separately.

Question 19. Differentiate between algae and fungi
Answer:

AlgaeFungi
1. Contain chlorophyll (green in colour). 2. Autotrophic nutrition. 3. Food is stored in the form of starch.1. Do not contain chlorophyll (non-green) 2. Heterotrophic nutrition. 3. Food is stored in the form of glycogen.

Question 20. Name the phylum of the following organisms, whose exclusive characteristics is given below:
(a) Hollow bones                                            (b) Jointed appendages
(c) Flat worm                                                   (d) Round worms, parasitic
(e) Soft body, muscular marine animal (f) Radially symmetrical, spiny skin.
Answer:
(a) Phylum chordata, subphylum—vertebrata, class—Aves
(b) Phylum—Arthropoda
(c) Phylum—Platyhelmithes
(d) Phylum—Aschelminthes
(e) Phylum—Mollusca
(f) Phylum—Echinodermata

Question 21. Give the characteristibs of amphibians.
Answer: Amphibians are vertebrates that lives on land and in water.
(a) They are cold-blooded.
(b) Heart is three-chambered.
(c) Fertilization is external.
(d) Respiration through lungs on land and through moist skin when in water. Example, Frog, Toads

Question 22. Give the characteristics of Aves.
Answer:
(a) Aves/birds can fly.
(b) Streamlined body.
(c) Hollow and light bones.
(d) Forelimbs are modified into wings.
(e) Warm-blooded animals, heart with four chambers.
(f) Egg laying animals.
(g) Beak present, teeth are absent.

Question 23. Why do most of the amphibians lay their eggs in water and reptiles lay their eggs on land?
Answer: Amphibians lay their eggs in water because the tadpeles or young, ones that hatch out of egg has gills at initial stages, that allows them; to breathe in water.
In case of reptiles the young ones that hatch out does not have gplls> and the hatching of eggs requires warmth that is given by the mother, reptile.

Question 24. Give the hierarchy of 5 kingdom classification of living world.
Answer:
NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms SAQ Q24

NCERT Solutions for Class 9 Science Chapter 7 Long Answer Type Questions

Question 1. What is the importance of classification?
Answer: Classification is important because:
(a) Classification makes the study of wide variety, of organisms, systematic and easier.
(b) It projects a picture of all organisms and their interrelation with each other.
(c) It provides a base for the study of other branches of biology.
(d) It is useful in the study of ecology, which deals with; the inter-relation of an organism with their environment.
(e) It helps to establish a hierarchy of groups of organisms.

Question 2. What are the characteristic features of mammals?
Answer: Characteristics features of mammals: –
(a) Body is covered with hair.
(b) Skin is provided with sweat and sebaceous glands.
(c) Heart is four-chambered.
(d) Fertilization is internal.
(e) Females have mammary glands to produce milk to nourish their young ones.
(f) External ear—pinna, present.
(g) Eyes have eye lids.
(h) Warm-blooded.
(i) Respiration through lungs,
(j) Body cavity divided’ into- thorax and1 abdomen by muscular diaphragm.

Question 3. What are the characteristic features of reptiles?
Answer: The characteristics of reptiles:
(a) Dry scaly, impermeable skin.
(b) Respiration through lungs.
(e) Cold-blooded
(d) Internal fertilization.
(e) Heart is three chambered’.
(f) Two pairs of pentadactyl limbs are present.

Question 4. What are the basis for classification of organisms?
Answer: The basis for classification are:
(a) Presence or absence of nucleus.
(b) Organisms are unicellular, or multicellular.
(c) Level of organisation.
(d) Autotrophic mode of nutrition or heterotrophic mode of nutrition.
(e) Of the organisms that perform photosynthesis (Plants), their level, or organisation of the body.
(f) Of the animals, how does the individuals body develop and organise its different parts.

Question 5. Give the characteristics of fiat worms, round worms and segmented worm. Give their phylum.
Answer:
NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms LAQ Q5

Flat wormsRound wormsSegmented worms
Phylum—PlatyhelminthesPhylum NematodaPhylum Annelida
Dorsoventrally flat, i.e., flat body from top to bottom.Body is cylindrical.Body is segmented from head to tail.
No true body cavity.Pseudocoelom (Sort of body (cavity).True body cavity.
Mostly hermaphrodite, i.e., male and female sex organs present in the same individual.Sexes are separate.May be unisexual or bisexual.

Question 6. Give the classification of the plant kingdom.
Answer:
NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms LAQ Q6

Question 7. Differentiate (5 points) between monocot and dicot plants.
Answer:

Monocot PlantsDicot Plants
1. Fibrous root 2. Parallel venation 3. Seeds with one cotyledon 4. Vascular bundles are scattered. 5. Flowers are trimerousTaproot Reticulate venation. Seeds with two cotyledons Vascular bundles are arranged in rings. Flowers are pentamerous, flowers or tetramerous

Question.8. Give the outline classification of animal kingdom.
Answer.
NCERT Solutions for Class 9 Science Chapter 7 Diversity in Living Organisms LAQ Q8

NCERT Solutions for Class 9 Science Chapter 7 Activity -Based Questions

Question 1.

  1.  We have heard of ‘desi’ cows and Jersey cows.
  2. Does a desi cow look like a Jersey cow?
  3. Do all desi cows look alike.
  4. Will we be able to identify a Jersey cow in a crowd of desi cows that don’t look like each other?
  5. What is the basis of our identification?

Answer:

  1. Desr cow is different in size’ and colour.
  2. Most of the desi cows look alike, not all.
  3. Yes, Jersey cow can be spotted’ from the group.
  4. Basis of identification:
  5. Size, horn shape, skin colour, height, etc.

Question 2.

  • Soak seeds of green gram, wheat, maize, peas and tamarind Once they become tender, try to split the seed. Do all the seeds break into two nearly equal halves?
  • The seeds that do are the dicot seeds and the seeds that don’t are then; monocot seeds.
  • Now take a look at the roots, leaves and flowers of these plants.
  • Are the roots, tap roots or fibrous?
  • Do the leaves have parallel or reticulate venation?
  • How many petals are found in the flowers of these plants?
  • Can you write down further characteristics of monocots and dicots on the basis of these observations?

Answer:

CharacteristicsGreen gramWheatMaizePeasTamarind
1. RootsTap rootFibrous rootFibrous rootTap rootTap root
2. CotyledonDicotyledon.MonocotyledonMonocotyledonDicotyledon.Dicotyledon.
3. Venation in leavesReticulateParallelParallelReticulateReticulate
4. Vascular bundleIn a ringNot in a ringNot in a ringIn a ringIn a ring
5. FlowersPentamerousTrimerousTrimerousPentamerousPentamerous

Question 3. Find out the. names of the following, animals and plants in as many: languages as you can.
Answer: It is difficult to remember names of a species in different languages This problem means there was a need for some system to create unifhrm naming convention: Hence system of nomenclature and classification was devised

Animals Plants
1. Frog—Rana tigrina 2. Human—Homo Sapiens 3. Peacock—Pam cristatus 4. Honeybee—Apis cerena, Apis indica.1. Touch me not—Mimosa pudica. 2. Neem—Azadirachta indica. 3. Maize—Zea mays.

NCERT Solutions for Class 9 Science Chapter 7 Value-Based Questions

Question 1. Many medicinal plants every year are getting extinct. A group of students who had gone for educational trip clicked photographs of endangered plants. These photograph were used by the school laboratory to study these plants.
(a) Name two endangered plants.
(b) Name any one medicinal plant and give its medicinal use.
(c) What value of students is reflected in the above act?
Answer:
(a) Two endangered plants are:
(i) Euphrasia
(ii) Ubnus rubra
(b) Aloe-vera. Juice of Aloe-vera is used in case of indigestion, treating dkin infection etc.
(c) Students are caring citizens, shows responsible behaviour.

Question 2. Due to global warming coral is getting diminished in all the oceans/ water bodies. People in Lakshadweep island protects their corals by not allowing people/tourist to scape take few pieces away.
(a) Name the phylum of coral.
(b) What is coral made up of.
(c) What values of people in Lakshadweep island is reflected?
Answer:
(a) Phylum of coral is coelenterata.
(b) Coral is made up of calcium carbonate.
(c) People in Lakshadweep island reflect the value of-being-responsible (Citizen, respecting environment and nature.

NCERT Solutions For Class 9 Science Chapter 6 Tissues

NCERT Solutions Class 9 Science Chapter 6 Tissues – Here are all the NCERT solutions for Class 9 Science Chapter 6. This solution contains questions, answers, images, step by step explanations of the complete Chapter 6 titled Tissues of Science taught in class 9. If you are a student of class 9 who is using NCERT Textbook to study Science, then you must come across Chapter 6 Tissues. After you have studied lesson, you must be looking for answers of its questions. Here you can get complete NCERT Solutions for Class 9 Science Chapter 6 Tissues in one place. For a better understanding of this chapter, you should also see Chapter 6 Tissues Class 9 notes , Science.

Topics and Sub Topics in Class 9 Science Chapter 6 Tissues:

  1. Tissues
  2. Are Plants and Animals Made of Same Types of Tissues?
  3. Plant Tissues
  4. Animal Tissues

These solutions are part of NCERT Solutions for Class 9 Science. Here we have given Class 9 NCERT Science Textbook Solutions for Chapter 6 Tissues.

IN-TEXT QUESTIONS SOLVED

NCERT Textbook for Class 9 Science – Page 69

Question 1. What is a tissue?
Answer: A group of cells that are similar in structure and work together to do a peculiar function is called tissue.

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Question 2. What is the utility of tissues in multicellular organisms?
Answer: Tissues provide structural strength, mechanical strength, show division of labour.

Formulae Handbook for Class 9 Maths and ScienceEducational Loans in India

Class 9 Science NCERT Textbook – Page 74

Question 1. Name types of simple tissues.
Answer: The types of simple tissues are parenchyma, collenchyma, sclerenchyma and aerenchyma.

Question 2. Where is apical meristem found?
Answer: Apical meristem is found at the tip of root or shoot of the plant.

Question 3. Which tissue makes up the husk of coconut?
Answer: The husk of coconut is made of sclerenchymatous tissue.

Question 4. What are the constituents of phloem?
Answer: Phloem is made up of four types of elements sieve tube, companion cells, phloem fibres and phloem parenchyma.

Class 9 Science NCERT Textbook – Page 78

Question 1. Name the tissue responsible for movement in our body.
Answer: 1. Muscular tissue, 2. Nervous tissue, combination of both the tissues are responsible for movement in our body.

Question 2. What does a neuron look like?
Answer: A neuron consists of a cell body with a nucleus and cytoplasm, from which long thin hair like parts arise. Each neuron has a single long part called the axon, and many small, short branched parts called dendrite. An individual nerve cell is called neuron, it may be up to a metre long.
NCERT Solutions For Class 9 Science Chapter 6 Tissues Intext Questions Page 78 Q2

Question 3. Give three features of cardiac muscles.
Answer: Feature of cardiac muscles
(1) Heart muscles (cardiac muscles) are cylindrical, branched and uninucleated
(2) They are striated muscle fibres.
(3) They are involuntary muscles, cannot be controlled by us.

Question 4. What are the Junctions of areolar tissue?
Answer: Areolar tissue are connective tissues found in animal. It is found between skin and muscles, around blood vessels and nerves and in the bone marrow.
It fills the space inside the organs, supports internal organs and helps in the repair of tissues.

Questions From NCERT Textbook for Class 9 Science

Question 1. Define the term “tissue”.
Answer: Group of cells that are similar in structure and perform same function is called a tissue.

Question 2. How many types of elements together make up the xylem tissue? Name them.
Answer: The xylem is made up of vessels, trachieds, xylem fibres and xylem parenchyma.

Question 3. How are simple tissues different from complex tissues in plants?
Answer: Simple tissues are made up of one type of cells which coordinate to perform a common function.
Complex tissues are made up of more than one type of cells. All these coordinate to perform a common function.

Question 4. Differentiate between parenchyma, collenchyma and sclerenchyma on the basis of their cell wall. 
Answer: Parenchyma: The cells have thin cell walls made up of cellulose. Collenchyma: The cells have cell walls thickened at the comers due to pectin deposition.
Sclerenchyma: Their walls are thickened due to lignin deposition.

Question 5. What are the functions of stomata?
Answer: The outermost layer of the cell is called epidermis and is very porous. These pores are called stomata. These stomata help in transpiration and exchange of gases.

Question 6. Diagrammatically show the difference between the three types of muscle fibres.
Answer: Striated muscles
(1) They are connected to bones (Skeletal muscles).
(2) They are voluntary muscles.
(3) The cells are long, cylindrical with many nucleus and are unbranched.
Smooth muscles
(1) They are found in alimentary canal and lungs.
(2) They are involuntary muscles.
(3) They are spindle in shape and have single nucleus.
Cardiac muscles
(1) They are found in heart.
(2) They are involuntary in action.
(3) They are branched and have one nucleus.
NCERT Solutions For Class 9 Science Chapter 6 Tissues Textbook Questions Q6

Question 7. What is the specific function of the cardiac muscle?
Answer: (1) Cardiac muscles cells are cylindrical, branched and uninucleated.
(2) They are involuntary muscles.
(3) They show rhythmically contraction and relaxation throughout life.
(4) Their rhythmic contraction and relaxation helps in pumping action of heart.

Question 8. Differentiate between striated, unstriated and cardiac muscles on the basis of their structure and location in the body.
Answer:

Question 9. Draw a labelled diagram of neuron.
Answer:

Question 10. Name the following:
(1) Tissue that forms the inner lining of our mouth.
(2) Tissue that connect muscle to bone in humans.
(3) Tissue that trar-carts food in plants.
(4) Tissue that siwea j’ut in our body.
(5) Connective tissue with a fluid matrix.
(6) Tissue present in the brain.
Answer: (1) Squamous epithelium (2) Tendons
(3) Phloem (4) Areolar tissue
(5) Blood (6) Nervous tissue

Question 11. Identify the type of tissue in the following: Skin, bark of tree, bone, lining of kidney tubule, vascular bundle.
Answer: (a) Skin—Striated squamous epithelium
(b) Bark of tree—Cork, protective tissue
(c) Bone—Connective tissue
(d) Lining of kidney tubule—Cuboidal epithelium tisse
(e) Vascular bundle—Conducting tissue

Question 12. Name the regions in which parenchyma tissue is present.
Answer: In the pith of the roots and stems. When it contains chlorophyll, it is called chlorenchyma, found in green leaves. In aquatic plants, parenchyma contains large air cavities and help them to float. Such type of parenchyma is called aerenchyma.

Question 13. What is the role of epidermis in plants?
Answer: Cells of epidermis forms a continuous layer without intercellular spaces. It protects all the parts of plants.

Question 14. How does the cork act as a protective tissue?
Answer: Cork acts as a protective tissue because its cells are dead and compactly arranged without intercellular spaces. They have deposition of suberin on the walls that make them impervious to gases and water.

Question 15. Complete the table:

Answer:

NCERT Solutions for Class 9 Science Chapter 6 Tissues (Hindi Medium)

NCERT Solutions for Class 9 Science Chapter 6 Tissues Hindi Medium 1
NCERT Solutions for Class 9 Science Chapter 6 Tissues Hindi Medium 2
NCERT Solutions for Class 9 Science Chapter 6 Tissues Hindi Medium 3
NCERT Solutions for Class 9 Science Chapter 6 Tissues Hindi Medium 4
NCERT Solutions for Class 9 Science Chapter 6 Tissues Hindi Medium 5
NCERT Solutions for Class 9 Science Chapter 6 Tissues Hindi Medium 6
NCERT Solutions for Class 9 Science Chapter 6 Tissues Hindi Medium 7
NCERT Solutions for Class 9 Science Chapter 6 Tissues Hindi Medium 8
NCERT Solutions for Class 9 Science Chapter 6 Tissues Hindi Medium 9
NCERT Solutions for Class 9 Science Chapter 6 Tissues Hindi Medium 10

MORE QUESTIONS SOLVED

NCERT Solutions for Class 9 Science Chapter 6 Multiple Choice Questions
Choose the correct option:
1. The cells of cork are dead and have a chemical in their walls that makes them impervious to gases and water. The chemical is
(a) lignin (b) suberin
(c) cutin (d) wax
2. The flexibility in plants is due to a tissue called,
(a) chlorenchyma (b) parenchyma
(c) sclerenchyma (d) collenchyma
3. The tissue present in the lining of kidney tubules and ducts of salivary glands is
(a) squamous epithelium tissue (b) glandular epithelium tissue
(4 cuboidal epithelium tissue (d) columnar epithelium tissue
4. The connective tissue that connects muscle to bone is called
(a) ligament (b) tendon
(d) cartilage (d) areolar
5. The tissue that helps in the movement of our body are
(a) muscular tissue (b) skeletal tissue
(c) nervous tissue (d) all of the above
6. Monocyte, basophil, eosinophil and neutrophil are the examples of different types of
(a) red blood cells (b) white blood cells
(c) areolar tissue (d) compact bone
7. The spindle shaped cells, uninucleated and unbranched are present in muscular tissue of 
(a) striated muscles (b) smooth muscles
(c) cardiac muscle (d) both (a) and (b)
8. Sieve tubes and companion cells are present in
(a) xylem (b) phloem
(c) cork (d) cambium
9. The size of the stem increases in the width due to
(a) apical meristem (b) intercalary meristem
(c) primary meristem (d) lateral meristem
10. Blood and lymph are types of
(a) muscular tissue (b) epithelial tissue
(c) connective tissue (d) permanent tissue
11. Cartilage and bone are types of
(a) muscular tissue (b) connective tissue
(c) meristematic tissue (d) epithelial tissue
12. Xylem and phloem are examples of
(a) epidermal tissue (b) simple tissue
(c) protective tissue (d) complex tissue
13. A tissue whose cells are capable of dividing and re-dividing is called
(a) complex tissue (b) connective tissue
(c) protective tissue (d) meristematic tissue
14. The tissue that helps in the secretion and absorption and is found in the inner lining of the alimentary canal is
(a) ciliated epithelium (b) cuboidal epithelium
(c) squamous epithelium (d) columnar epithelium
Answer: 1—(b), 2—(d), 3—(c), 4—(b), 5—(d), 6—(b), 7—(b), 8—(b), 9—(d), 10—(c),11—(b), 12—(d), 13—(d), 14—(d).

NCERT Solutions for Class 9 Science Chapter 6 Very Short Answer Type Questions

Question 1. Name the tissues responsible for the movement of the body.
Answer: Muscle tissue and nervous tissue

Question 2. How does neuron look like?
Answer: A neuron is the unit cell of nervous tissue. It is a thread-like structure with cell body and axon.

Question 3. Name the types of simple tissues.
Answer: (a) Parenchyma (b) Collenchyma (c) Sclerenchyma

Question 4. Name the types of complex tissues.
Answer: Xylem and phloem.

Question 5. Where is apical meristem found? .
Answer: It is present at the growing tips of stem and root, it increases the length of the stem and roots.

Question 6. Which tissue make up the husk of coconut?
Answer: Sclerenchyma.

Question 7. What are the constituents of phloem?
Answer: Phloem constitutes the sieve tubes, companion cell, phloem parenchyma and phloem fibres.

Question 8. Define aerenchyma.
Answer: When the cells have air-filled large cavities of parenchyma, it is called aerenchyma. Aerenchyma helps aquatic plants in floating.

Question 9. What is the utility of tissues in multicellular organisms?
Answer: It helps in growth, organisation of different organs and performing functions.

Question 10. Name the two types of tissues.
Answer: Plant tissues and animal tissues.

Question 11. Name the two types of plant tissue.
Answer: Meristematic tissue and permanent tissue.

Question 12. What is differentiation?
Answer: The process of taking up a permanent shape, size and function by cells is called differentiation.

Question 13. Name the three types of meristematic tissues.
Answer: The three types are:
(a) Apical tissue—tips of root and shoot
(b) Lateral tissue—sides of stem
(c) Intercalary tissue—at nodes

Question 14. Where is apical tissue found?
Answer: Present at the tips of roots and stems.

Question 15. Tissues present at the lateral surface of the stem are called apical tissues. Put (T) if true and put (F) if false.
Rewrite the answer if (F).
Answer: (F). Tissues present at the lateral surface of the stem are called lateral tissue.

Question 16. Which tissues are present at the nodes of the plants?
Answer: Intercalary tissue.

Question 17. What are the various types of blood cells?
Answer: There are three types:
(a) RBC’s
(b) WBC’s and
(c) Platelets.

Question 18. What are tracheids?
Answer: They are elongated cells with tapering ends.

Question 19. What are guard cells?
Answer: Each stomata is bounded by a pair of specialised kidney-shaped epidermal cells called guard cells.

Question 20. Epithelial tissue is the simplest tissue. Write (F) for false or (T) for true.
Answer: (T).

Question 21. What are the functions of cuboidal epithelium?
Answer: It helps in absorption, excretion, secretion, it also provides mechanical support.

NCERT Solutions for Class 9 Science Chapter 6 Short Answer Type Questions

Question 1. Give four differences between bone and cartilage.
Answer:
NCERT Solutions For Class 9 Science Chapter 6 Tissues SAQ Q1

Question 2. Give the functions of bone.
Answer: The functions of bone are:
(i) It provides shape to the body.
(ii) It provides skeletal support to the body.
(iii) It anchors the muscles.
(iv) It protects the vital body organs like brain, lungs, etc.

Question 3. Give the functions of cartilage. .
Answer: (i) It provides support and flexibility to the body parts.
(ii) It smoothens surface at joints.

Question 4. Fill in the blanks:
(i) Water and minerals are conducted by ………………….
(ii) In higher plants food is conducted by ……………………..
(iii) Blood is a ……………. tissue.
(iv) Bone consists of………….cells.
(v) Cartilage consists of………………..cells.
(vi) Fibres are absent in………….type of connective tissue.
Answer: (i) Xylem (ii) Phloem
(iii) Connective (iv) Osteocyte
(v) Chondrocyte (vi) Blood

Question 5. What are the functions of areolar tissue?
Answer: Functions are:
(i) It helps in repair of tissues after an injury.
(ii) It also helps in combating foreign toxins.
(iii) It fixes skin to underlying muscles.

Question 6. Give difference between xylem and phloem.
Answer:
NCERT Solutions For Class 9 Science Chapter 6 Tissues SAQ Q6
Question 7. What are fibres?
Answer: Fibres consist of very long, narrow and thick cells. Example, jute fibre.

Question 8. Name the tissues for the following:
(a) Stores fat in animal body.
(b) Divides and re-divides to grow in plants.
(c) Tissue that joins hone to hone.
(d) Covers the external surface of animal body.
Answer: (a) Adipose tissue
(b) Meristematic tissue .
(c) Ligament
(d) Epithelial tissue.

Question 9. What is stomata?
Answer: Stomata are small pores present on the surface of a leaf which helps in the exchange of gases and in transpiration.

Question 10. Why does epidermal tissue have no intercellular space?
Answer: The epidermal (layer) tissue forms a protective outer covering for the plants and it protects the internal parts of the plant. It aid in the protection against loss of water, mechanical injury and invasion by parasitic fungi.
For this protective role to play the continuation of cells is necessary, hence it does not have intercellular space.

Question 11. Name and give the function of each cell of xylem:.
Answer: Xylem consists of tracheids, vessels, xylem parenchyma and xylem fibres.
Tracheids and vessels—Allows the transport of water and minerals.
Xylem parenchyma—Stores food and helps in the sideways conduction of water.
Xylem fibres—Are supportive in function.

Question 12. What is the function and location of stratified squamous epithelium?
Answer: Stratified squamous epithelium is present in the skin. The layers of cells are arranged to prevent wear and tear.

Question 13. Give difference between ligament and tendon.
Answer:
NCERT Solutions For Class 9 Science Chapter 6 Tissues SAQ Q13

Question 14. Give difference between striated muscles and unstriated muscles.
Answer:
NCERT Solutions For Class 9 Science Chapter 6 Tissues SAQ Q14

Question 15. State the difference between bone and blood.
Answer:
NCERT Solutions For Class 9 Science Chapter 6 Tissues SAQ Q15

Question 16. Name all different types of tissues present in animal.
Answer: There are four main types of tissues present in animal. ‘
(a) Epithelial tissue present on the outer and inner lining of the body.
(b) Muscular tissue are made up of muscles, help in movement.
(c) Connective tissue connects the different organs in the body.
(d) Nervous tissue consists of nerve cells and are present in the nervous system.

Question 17. Why is blood called connective tissue?
Answer: The blood is composed of cells and plasma. Plasma is a fluid and cells like red blood cells, white blood cells and platelets are present in it. All these cells are connected due to plasma. It also transports food, water to different parts of the body and connects them.

Question 18. Name three types of muscle tissues and give function of each.
Answer: Three types of muscle tissues are:
(a) Striated muscle (b) Smooth muscle (c) Cardiac muscle
(a) Striated muscle: These muscles show alternate light and dark bands or striations. They are involuntary and present in skeletal tissues,, help in movement of body and bones.
(b) Smooth muscle: These are involuntary muscles, control the movement of food in alimentary canal, contraction and relaxation of blood vessels. Present in iris, uterus etc.
(c) Cardiac muscle: These muscles are present in heart, help in the rhythmic contraction and relaxation throughout the life.

Question 19. State the difference between simple tissues of plants.
Answer: The simple tissues of plants are:
(i) Parenchyma (v) Collenchyma (iii) Sclerenchyma
NCERT Solutions For Class 9 Science Chapter 6 Tissues SAQ Q19

Question 20. With the help of diagram show the difference between striated muscle fibre, smooth muscle fibre and cardiac muscle fibre.
Answer:
NCERT Solutions For Class 9 Science Chapter 6 Tissues SAQ Q20

NCERT Solutions For Class 9 Science Chapter 6 Tissues SAQ Q20.1

Question 21. Name different types of meristematic tissue and draw diagram to show their location.
Answer: The 3 different types of meristematic tissue are:
(a) Apical meristem—Function: growth in length.
(b) Lateral meristem—Function: growth in thickness.
(c) Intercalary meristem—Function: growth in intemodes.
NCERT Solutions For Class 9 Science Chapter 6 Tissues SAQ Q21

Question 22. Explain the structure, function and location of nervous tissue.
Answer: Structure: Nervous tissue consists of cells called nerve cells joined end to end (neurons). A neuron (nerve cell) consists of a cell body with nucleus and cytoplasm. From these cell body a long thin hair-like parts arise called axon and many short branched parts called dendrites.
Location: Nervous tissue are present in brain, spinal cord and nerves. Function: Nervous tissue receives the stimuli and transmit the stimulus rapidly from one place to another within the body. The nerve impulse allows us to move our muscles and respond to any stimuli.

Question 23. Give the flow chart of plant tissues.
Answer:
NCERT Solutions For Class 9 Science Chapter 6 Tissues SAQ Q23

NCERT Solutions for Class 9 Science Chapter 6 Long Answer Type Questions

Question 1. Write a note on plant tissues.
Answer: Plant tissues consist of two main types of tissue.
NCERT Solutions For Class 9 Science Chapter 6 Tissues LAQ Q1
Parenchyma: Present in soft parts of the plant.
Collenchyma: Provides mechanical support to plant present in stalks. Sclerenchyma: They provide strength and flexibility to the plants.
Xylem: Conduct water in plants from root to shoot. Consists of tracheids, vessels, xylem parenchyma and xylem fibres.
Phloem: Conduct food to all parts of plant. Consist of sieve tubes, companion cell, phloem parenchyma and phloem fibres.

Question 2. Show the types of animal tissues using flow chart.
Answer:
NCERT Solutions For Class 9 Science Chapter 6 Tissues LAQ Q2

Question 3. What is connective tissue? Explain its types.
Answer: The connective tissue consists of different types of cells, all of them perform same function.
NCERT Solutions For Class 9 Science Chapter 6 Tissues LAQ Q3
Areolar connective tissue: It is found between the skin and muscles, around blood vessels and nerves and in the bone marrow.
Areolar tissue fills the space inside the organs. It supports internal organs and helps in repair of tissues.
Adipose tissue: Adipose tissue stores fat, found below the skin and between internal organs. The cells of this tissue are filled with fat globules. It acts as insulator due to fat storage.
Blood: It has a fluid called plasma, in plasma are present red blood cells, white blood cells and platelets. Blood flows all over the body and helps in the transport of gases, digested food, hormones and waste material to different parts of the body.
Lymph: Lymph carries digested fat and lot of white blood cells in the plasma. Bone: It forms the framework that supports the body. It supports the different parts of our body. It is strong and non-flexible tissue.
Cartilage: It is present in nose, ear, trachea and larynx. It smoothens bone surfaces at joints.
Tendon: It connects bone and muscles. These tissues are fibrous, flexible and with lot of strength.
Ligament: It connects bone to ‘bone. It is elastic, has lot of strength.

Question 4.Describe ‘epidermis’ in plants.
Answer: Epidermis forms the entire outermost layer of the plant. It is made up of single cell layer. It protects all the internal parts of the plant.
On aerial parts, epidermis secretes waxy, water-resistant layer on their outer surface. This helps in protection against loss of water, mechanical injury and invasion of parasitic fungi.
In leaves, epidermis consists of small pores called stomata. These pores helps in the transpiration and exchange of gases, like oxygen and carbon dioxide for plants.
In roots, epidermis have long hair-like parts that provide greater surface for water absorption.
In desert plants, epidermis has a thick waxy coating of cutin which acts as a water proofing agent.

Question 5. Explain the “complex tissue” of plants.
Answer: Complex tissues are made up of more than one type of cells. All these cells co-ordinate to perform common function. These are—xylem and phloem. Both are conducting tissues and form a vascular bundle.
Xylem consists of—tracheids, vessels, xylem parenchyma and xylem fibres. Most of these cells are dead. Tracheids and vessels helps in water transportation, parenchyma stores food and helps in the sideways conduction of water and fibres are mainly supportive in function.
Phloem is made up of four types of elements—sieve tubes, companion cells, phloem fibres and phloem parenchyma. It helps in the transportation of food in both the directions, i.e. from leaves to roots and to other parts of the plant.

NCERT Solutions for Class 9 Science Chapter 6 Activity-Based Questions

Question 1. • Take two glass jars and fill them with water.
• Now, take two onion bulbs and place one on each jar, as shown in the figure given below.
NCERT Solutions For Class 9 Science Chapter 6 Tissues Activity Based Q1
• Observe the growth of roots in both the bulbs for a few days.
• Measure the length of roots on day 1, 2 and 3.
• On day 4, cut the root tips of the onion bulb in jar 2 by about 1cm. After this, observe the growth of roots in both the jars and measure their lengths each day for five more days and record the observations in tables, like the table
From the above observations, answer the following questions:
(a) Which of the two onions has longer roots? Why?
(b) Do the roots continue growing even after we have removed their tips?
(c) Why would tips stop growing in jar 2 after we cut them?
Answer: (a) The onion in jar 1 has longer roots, as the growth of roots continues in it due to intact root tips.
(b) The roots did not continue to grow in jar 2 after cutting down their tips.
NCERT Solutions For Class 9 Science Chapter 6 Tissues Activity Based Q1.1
(c) The tips of root stopped growing in jar 2 because the tips of these roots were cut down and the tissues which helps in the growth of roots i.e., meristematic tissues are removed from it.

Question 2. • Take a plant stem and with the help of your teacher cut into very thin slices or sections.
• Now, stain the slices with safranin. Place one neatly cut section on a slide, and put a drop of glycerine.
• Cover with a cover-slip and observe under a microscope. Observe the various types of cells and their arrangement.
• Answer the following on the basis of your observations:
(a) Are all cells similar in structure?
(b) How many types of cells can be seen?
(c) Can we think of reasons why there would be so many types of cells?
NCERT Solutions For Class 9 Science Chapter 6 Tissues Activity Based Q2
Answer:
(a) No, all cells are not similar in structure, we see variety of cells with different shape and size.
(b) We can see at least ten different types of cells in the slide. .
(c) Yes, there are variety of cells so that each group of cell does a specific role in the overall growth of plant.

Question 3. • Take a freshly plucked leaf of Rheo.
• Stretch and break it by applying pressure.
• While breaking it, keep it stretched gently so that some peel or skin projects out from the cut.
• Remove this peel and put it in a petridish filled with water.
• Add a few drops of safranin.
• Wait for a couple of minutes and then transfer it onto a slide. Gently place a cover slip over it.
Answer: (a) The slide shows epidermal cells with stomatal pores as shown in Fig. (a).
(b) On focusing stomata pores under microscope. We can see guard cells and stomata pore as shown in Fig. (b).
NCERT Solutions For Class 9 Science Chapter 6 Tissues Activity Based Q3

NCERT Solutions for Class 9 Science Chapter 6 Value-Based Questions

Question 1. A group of students completed the project of finding the botanical names of all the trees present in the school campus. They prepared metal plates with names carved on it, to fix it on the plant trunks. Shreya was concerned that if the metal plate is fixed into tree many cells of the tree may get damaged. But the group members explained her that the outer layer of trunk does not have living cells and there won’t be any damage to the tree.
(a) What type of cells are present on the outer layer of the bark/tree trunk?
(b) How does the cprk act as a protective tissue?
(c) What value of the group is seen in the above cast?
Answer: (a) On the outer layer of the tree trunk/bark all thick layer of dead cells is present which acts as protective tissue.
(b) In cork, all cells are dead without intercellular spaces, the walls of the cells have deposition of suberin.
(c) The students in a group show team effort, peer learning and co-operatiye.

Question 2. A paralytic patient was unable to walk. ‘The family member of the patient took the outmost care of the patient.
(a) Name two tissues responsible for the movement of a body.
(b) Name the tissues present in brain and spine.
(c) What value of the family members is seen in the above case?
Answer: (a) The two tissues responsible for movement of the body are muscular tissue and nervous tissue.
(b) The tissues present in brain and spine are nervous tissues.
(c) The family members showed the value of being caring, responsible, dutiful and kind.