Science Ncert Exemplar Solutions for Class 10 Science Chapter 14 Sources Of Energy are provided here with simple step-by-step explanations. These solutions for Sources Of Energy are extremely popular among class 10 students for Science Sources Of Energy Solutions come handy for quickly completing your homework and preparing for exams. All questions and answers from the Science Ncert Exemplar Book of class 10 Science Chapter 14 are provided here for you for free. You will also love the ad-free experience on Meritnation’s Science Ncert Exemplar Solutions. All Science Ncert Exemplar Solutions for class 10 Science are prepared by experts and are 100% accurate.
Page No 102:
Question 1:
Which of the following is a non-renewable source of energy?
(a) Wood
(b) Sun
(c) Fossil fuels
(d) Wind
Answer:
The source energy which is limited in amount and cannot be replenished is known as non-renewable source of energy. In the given options, fossil fuels are present on earth in limited amount. Therefore, it is the non-renewable source of energy.
Hence, the correct answer is option C.
Page No 102:
Question 2:
Acid rain happens because
(a) sun leads to heating of upper layer of atmosphere
(b) burning of fossil fuels release oxides of carbon, nitrogen and sulphur in the atmosphere
(c) electrical charges are produced due to friction amongst clouds
(d) earth atmosphere contains acids
Answer:
The oxides of carbon, nitrogen and sulphur that are released on burning fossil fuels are acidic oxides. These lead to acid rain which affects our water and soil resources.
Hence, the correct answer is option B.
Page No 102:
Question 3:
Fuel used in thermal power plants is
(a) water
(b) uranium
(c) biomass
(d) fossil fuels
Answer:
Fuel used in thermal power plants is fossil fuel. In thermal power plant fossil fuel is used for generation of electricity.
Hence, the correct answer is option D.
Page No 102:
Question 4:
In a hydro power plant
(a) Potential energy possessed by stored water is converted into electricity
(b) Kinetic energy possessed by stored water is converted into potential energy
(c) Electricity is extracted from water
(d) Water is converted into steam to produce electricity
Answer:
In a hydro power plant, potential energy possessed by stored water is converted into electricity. In hydro power plant water is stored upto certain height by constructing dam and then it is slowly released to generate the electricity.
Hence, the correct answer is option A.
Page No 103:
Question 5:
Which is the ultimate source of energy?
(a) Water
(b) Sun
(c) Uranium
(d) Fossil fuels
Answer:
Sun is the ultimate source of energy, because most of the energy related requirements on earth fulfilled by the energy radiated from the sun. Also, the fossil fuel, biogas, etc are formed indirectly from the sun.
Hence, the correct answer is option B.
Page No 103:
Question 6:
Which one of the following forms of energy leads to least environmental pollution in the process of its harnessing and utilisation?
(a) Nuclear energy
(b) Thermal energy
(c) Solar energy
(d) Geothermal energy
Answer:
Solar energy leads to least environmental pollution in the process of its harnessing and utilisation.
Hence, the correct answer is option C.
Page No 103:
Question 7:
Ocean thermal energy is due to
(a) energy stored by waves in the ocean
(b) temperature difference at different levels in the ocean
(c) pressure difference at different levels in the ocean
(d) tides arising out in the ocean
Answer:
Ocean thermal energy is due to temperature difference at different levels in the ocean.
Hence, the correct answer is option B.
Page No 103:
Question 8:
The major problem in harnessing nuclear energy is how to
(a) split nuclei?
(b) sustain the reaction?
(c) dispose off spent fuel safely?
(d) convert nuclear energy into electrical energy?
Answer:
Disposal of the spent fuel safely is the major problem in harnessing nuclear energy.
Hence, the correct answer is option C.
Page No 103:
Question 9:
Which part of the solar cooker is responsible for green house effect?
(a) Coating with black colour inside the box
(b) Mirror
(c) Glass sheet
(d) Outer cover of the solar cooker
Answer:
Glass sheet of the solar cooker is responsible for green house effect. It captures and traps the energy. Due to the trapping of the energy from the sun, the temperature inside the solar cooker increases which is known as green house effect.
Hence, the correct answer is option C.
Page No 103:
Question 10:
The main constituent of biogas is
(a) methane
(b) carbon dioxide
(c) hydrogen
(d) hydrogen sulphide
Answer:
The constituent of the biogas are methane, carbon dioxide, hydrogen sulphide, etc. The main constituent of biogas is methane because its presence is 75%.
Hence, the correct answer is option A.
Page No 103:
Question 11:
The power generated in a windmill
(a) is more in rainy season since damp air would mean more air mass hitting the blades
(b) depends on the height of the tower
(c) depends on wind velocity
(d) can be increased by planting tall trees close to the tower
Answer:
The power generated in a windmill depends on wind velocity. The more the wind speed, the more will be the power generated and vice-versa.
Hence, the correct answer is option C.
Page No 104:
Question 12:
Choose the correct statement
(a) Sun can be taken as an inexhaustible source of energy
(b) There is infinite storage of fossil fuel inside the earth
(c) Hydro and wind energy plants are non polluting sources of energy
(d) Waste from a nuclear power plant can be easily disposed off
Answer:
Sun can be taken as an inexhaustible source of energy. The sun is the renewable source of energy.
Hence, the correct answer is option A.
Page No 104:
Question 13:
In a hydroelectric power plant more electrical power can be generated if water falls from a greater height because
(a) its temperature increases
(b) larger amount of potential energy is converted into kinetic energy
(c) the electricity content of water increases with height
(d) more water molecules dissociate into ions
Answer:
In a hydroelectric power plant more electrical power can be generated if water falls from a greater height because larger amount of potential energy is converted into kinetic energy.
Hence, the correct answer is option B.
Page No 104:
Question 14:
Choose the incorrect statement regarding wind power
(a) It is expected to harness wind power to minimum in open space
(b) The potential energy content of wind blowing at high altitudes is the source of wind power
(c) Wind hitting at the blades of a windmill causes them to rotate The rotation thus achieved can be utilised further
(d) One possible method of utilising the energy of rotational motion of the blades of a windmill is to run the turbine of an electric generator
Answer:
The high speed or kinetic energy content of wind blowing at high altitudes is the source of wind power. It is not the potential energy.
Hence, the correct answer is option B.
Page No 104:
Question 15:
Choose the incorrect statement
(a) We are encouraged to plant more trees so as to ensure clean environment and also provide bio-mass fuel
(b) Gobar-gas is produced when crops, vegetable wastes etc., decompose in the absence of oxygen
(c) The main ingredient of bio-gas is ethane and it gives a lot of smoke and also produces a lot of residual ash
(d) Bio-mass is a renewable source of energy
Answer:
The main constituent of biogas is not ethane. The main constituent of biogas is methane. It constitute 75% of the biogas.
Hence, the correct answer is option C.
Page No 104:
Question 16:
Why is there a need to harness non-conventional sources of energy? Give two main reasons.
Answer:
The two main reasons to harness non-conventional sources of energy are:
1. The non-conventional source of energy are not limited in amount. It is not going to replenish soon.
2. It does not pollute the environment. It is environment friendly.
Page No 104:
Question 17:
Write two different ways of harnessing energy from ocean.
Answer:
The two different ways of harnessing energy from ocean are:
- Ocean Thermal Energy: It is the energy obtained, due to the temperature difference at the surface and in depth of the ocean. It arises due to the heating of the surface of the ocean by the sun and the lower surface remains cold.
- Tidal Energy: It is the energy obtained, due to the high tides of the ocean. It arises due to the gravitational pull of the moon on the earth.
Page No 104:
Question 18:
What steps would you suggest to minimise environmental pollution caused by burning of fossil fuels?
Answer:
Few steps to minimise environmental pollution caused by burning of fossil fuels are
1. Planting more and more tress i.e Afforestation.
2. Using electric vehicles.
3. Fitting solar panels on the roofs.
Page No 105:
Question 19:
What is the role of a plane mirror and a glass sheet in a solar cooker?
Answer:
Plane mirror reflects the sunlight into the solar cooker thereby increasing the intensity of sunlight in the solar cooker. Glass sheet helps in trapping the sunlight in the solar cooker thereby increasing the temperature inside the cooker.
Page No 105:
Question 20:
Mention three advantages of a solar cell?
Answer:
Three advantages of a solar cell are
1. It does not cause any pollution.
2. It can be set up in remote areas.
3. It requires very less maintenance.
Page No 105:
Question 21:
What is biomass? What can be done to obtain bio-energy using biomass?
Answer:
Biomass is animal or plant material like wood, crop waste, leaves etc that is used for energy production. Following are the things that can be done to obtain bio-energy using biomass
1. By burning cowdung cakes
2. By burning wood
3. By producing biogas.
Page No 105:
Question 22:
What are the limitations in obtaining energy from wind?
Answer:
1. Wind energy can be harnessed only if wind speed exceeds 15 kmph.
2. Large area is required for setting wind turbines.
Page No 105:
Question 23:
Which is the process used to harness nuclear energy these days? Explain it briefly.
Answer:
The process used to harness nuclear energy these days is nuclear fission.
Nuclear fission is the nuclear reaction in which a heavy nucleus is hit by neutron due to which it splits into lighter nuclei. In this process, lot of energy is released. Controlled nuclear reaction is done in specially designed nuclear reactors.
Page No 105:
Question 24:
How can solar energy be harnessed? Mention any two limitations in using solar energy. How are these limitations overcome?
Answer:
Solar energy can be harnessed in many ways, one of the way to harness the solar energy is by using solar cooker. Solar cooker is a device which is used to cook food by using solar energy.
The two limitations in using solar energy are:
- The solar energy is not available in night. It means it is day dependent.
- The maximum energy has to fall on the device, for this every time the alignment has to be changed as per the direction of the sun light.
Page No 105:
Question 25:
Make a list of conventional and non-conventional sources of energy. Give a brief description of harnessing one nonconventional source of energy.
Answer:
The conventional sources of energy are: petroleum, coal, fossil fuel, natural gas, etc.
The non-conventional sources of energy are: geothermal energy, wind energy, hydroelectric energy, ocean energy, solar energy, etc.
Solar energy: This is the non-conventional source of energy in which solar energy is harnessed in many ways by using devices like solar cell, solar cooker, etc. In solar cooker, it is used to trap the heat energy and cook the food.
Page No 105:
Question 26:
Why is there a need for harnessing non-conventional sources of energy? How can energy be harnessed from the sea in different ways?
Answer:
There is a need for harnessing non-conventional sources of energy because of the following advantages:
- It is almost pollution free
- It is not going to extinct soon
- The waste release is easy to dispose
- Ocean Thermal Energy
- Wave Energy
- Tidal Energy
Page No 105:
Question 27:
What are the environmental consequences of using fossil fuels? Suggest the steps to minimise the pollution caused by various sources of energy including non-conventional sources of energy.
Answer:
The environmental consequences of using the fossil fuels are:
- It causes lot of environmental pollution.
- The waste released is not easily disposable.
- It is limited in quantity.
- It results in acid rain.
- It increases the global warming and causes green house effect.
- Planting more trees
- Using solar cooker
- Using CNG in automobile instead of petroleum
- Avoid use of conventional source of energy
Page No 105:
Question 28:
Energy from various sources is considered to have been derived from the sun. Do you agree? Justify your answer.
Answer:
Yes, the various energy resources like ocean thermal energy, wind energy, fossil fuels, etc. derive there energy from sun. The ocean thermal energy is due to the uneven heating of the different layers of ocean by sun. The wind energy is due to the uneven heating of the land at different location. The fossil fuel is obtained from the dead remains of the plant and animal. The existence of the plant and animal depends on the sun.
Page No 105:
Question 29:
What is biomass? Explain the principle and working of a biogas plant using a labelled schematic diagram.
Answer:
The source of fuel which is produced from the plant and animal remain are called biomass.
In biogas plant, the remains of plant and animal are used to make the slurry. This slurry is poured into a dome like structure. The slurry undergoes the endothermic reaction. Because of this reaction, biogas is released which is collected at the top of the dome. Finally from the exit portal the gas is taken out.
The labelled diagram of biogas plant: 
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