NCERT Exemplar Class 10 Science Chapter 14 Sources Of Energy

Chapter 14 Source Of Energy NCERT Exemplar for class 10 Science

NCERT Exemplar Solutions for Class 10 Science Chapter 14 source of energy are an essential study tool for the students to pass the CBSE Class 10 examination with flying colors. This study material presents you with the answers to the questions provided in the NCERT. Exemplar aids you in gaining precise knowledge on different kinds of questions to be asked in the examinations.

Chapter 14 in class 10th Science deals with the study of electromagnetic effects etc. In this chapter, students will study about different sources and types of energies etc . However, the main objective is to help students gain practical knowledge. This exemplar has answers to different kinds of questions such as MCQs, and long answer questions that will help you to practice different types of questions.

NCERT Exemplar questions will add up to your knowledge gained through textbooks, and this will help you when you face competitive examinations. Students can practice the NCERT Exemplar class 10 Chapter 14 offline as well by downloading the solutions in PDF format.

Scroll down, to ace the content below!!

Question 1: Acid rain happens because

(a) Earth’s atmosphere contains acids

(b) burning of fossil fuels releases oxides of carbon, nitrogen and sulphur into the atmosphere

(c) sun leads to heating of the upper layer of the atmosphere

(d) electrical charges are produced due to friction amongst clouds

Answer 1: (b)

Explanation:

Rainwater combines with atmospheric carbon, nitrogen, and sulphur oxides to form acid rain.

Question 2: Fuel used in thermal power plants is

(a) biomass

(b) uranium

(c) water

(d) fossil fuels

Answer 2: (d) fossil fuels

Explanation:

The primary fossil fuel utilised in thermal power plants is coal. Petroleum and natural gas are also used in addition to coal.

Question 3: In a hydropower plant

(a) Potential energy possessed by stored water is converted into electricity

(b) Water is converted into steam to produce electricity

(c) Electricity is extracted from water

(d) Kinetic energy possessed by stored water is converted into potential energy

Answer 3: (a)

Explanation:

Dammed water has the ability to produce energy. It has potential energy when it is released, which is used to turn the turbines. Electricity is produced via turbines.

Question 4: Which is the ultimate source of energy?

(a) Water

(b) Sun

(c) Fossil fuels

(d) Uranium

Answer 4: (b)

Explanation:

Solar energy is used by plants to make food. Plant remains are used to create fossil fuels. Therefore, all energy comes from the Sun, either directly or indirectly.

Question 5: Which one of the following forms of energy leads to the least environmental pollution in the process of harnessing and utilisation?

(a) Geothermal energy

(b) Thermal energy

(c) Solar energy

(d) Nuclear energy

Answer 5: (c)

Explanation:

Metals like uranium, which emit dangerous radiation that can harm living things, are used in nuclear energy. Coal is used to generate thermal energy, which pollutes the air by releasing sulphur and carbon dioxide. In the case of geothermal energy, the pressure from the heat from the core, which can occasionally be extremely intense and dangerous, absorbs the energy.

Question 6: A solar water heater cannot be used to get hot water on

1. A windy day
2. A cloudy day
3. A hot day
4. A sunny day

Answer 6: b) A cloudy day

A solar water heater uses solar energy to heat water. The sunlight is reflected back into the sky by the clouds during overcast days because it isn’t strong and bright enough. As a result, the Sun cannot reach the ground. As a result, the solar water heater won’t be able to heat the water using solar energy.

Question 7: Which of the following is not an example of a biomass energy source?

1. Wood
2. Coal
3. Nuclear energy
4. Gobar-gas

Answer 7: c) Nuclear energy.

Animal and plant wastes are used to create biomass. These deceased plants and animals undergo a chemical transformation as a result of their interactions with water and sunlight. However, nuclear energy is created when atoms fuse and split, releasing enormous amounts of energy in the process. It is possible to carry out nuclear fusion and fission without sunshine.

Wood is a component of plants, gobar gas is made from animal waste, and coal is made from the decomposing bodies of plants and animals. They are all results of biomass energy products.

Question 8: Most energy sources we use represent stored solar energy. Which of the following is not ultimately derived from the Sun’s energy?

1. Geothermal energy
2. Biomass
3. Nuclear energy
4. Wind energy

Answer 8: c) Nuclear energy.

Nuclear fusion and nuclear fission are both sources of nuclear energy. When uranium atoms are subjected to nuclear fission, low-energy neutrons cause the atom to divide into two relatively lighter nuclei. Lighter nuclei are fused together to create relatively heavier nuclei in nuclear fusion. Nuclear reactions can occur without sunshine and yield enormous amounts of energy.

Geothermal energy is produced from the heat that is deep within the earth’s crust and has been stored there as energy. The wind is caused by the uneven heating of the earth’s surface, while biomass is made from the dead remnants of plants and animals.

Question 9: Ocean thermal energy is due to

(a) pressure difference at different levels in the ocean

(b) temperature difference at different levels in the ocean

(c) energy stored by waves in the ocean

(d) tides arising out in the ocean

Answer 9: (b)

Explanation:

Energy primarily from the surface is used to boil the volatile liquid, whereas vapours from these are utilised to turn the turbine.

Question 10: The major problem in harnessing nuclear energy is how to

(a)convert nuclear energy into electrical energy?

(b) sustain the reaction?

(c) dispose of spent fuel safely?

(d) split nuclei?

Answer 10: (c)

Explanation:

Highly radioactive material is created by nuclear power reactors. They pose a serious hazard to living things when they are discharged into the environment. So, one of the biggest challenges in using nuclear energy is safely disposing of the spent material.

Question 11: Which part of the solar cooker is responsible for the greenhouse effect?

(a) Outer cover of the solar cooker

(b) Mirror

(c) Glass sheet

(d) Coating with black colour inside the box

Answer 11: (c)

Explanation:

The atmosphere’s ability to trap heat is what causes the greenhouse effect. Heat is created due to the presence of greenhouse gases like CO2 and SO2. Similar events take place in solar cookers. The glass sheet reflects the solar energy trapped and causes the food to cook.

Question 12: The main constituent of biogas is

(a) methane

(b) hydrogen sulphide

(c) hydrogen

(d) carbon dioxide

Answer 12: (a)

Explanation:

The primary byproduct of biogas is methane gas. Methane makes up about 70% of the gas produced, with the remainder being made up of ammonia and carbon dioxide.

Question 13: The power generated in a windmill

(a) can be increased by planting tall trees close to the tower

(b) depends on the height of the tower

(c) depends on wind velocity

(d) is more in the rainy season since damp air would mean more air mass hitting the blades

Answer 13: (c)

Explanation:

High wind speeds will cause the turbine to spin more quickly. As a result, more electricity will be generated.

Question 14: Choose the correct statement

(a) Sun can be taken as an inexhaustible source of energy

(b) Waste from a nuclear power plant can be easily disposed of

(c) Hydro and wind energy plants are non-polluting sources of energy

(d) There is infinite storage of fossil fuel inside the earth

Answer 14: (a)

Explanation:

A finite source, fossil fuels are. By altering the environment and having an impact on the land usage, habitations, and natural ecosystems in the dam region, hydro and wind energy projects can have significant negative environmental effects. The primary challenge a nuclear facility faces is how to dispose of its waste.

Question 15: Choose the INCORRECT statement regarding wind power

(a) 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

(b) The potential energy content of wind blowing at high altitudes is the source of wind power

(c) It is expected to harness wind power to a minimum in open space

(d) Wind hitting the blades of a windmill causes them to rotate. The rotation thus achieved can be utilised further

Answer 15: (b)

Explanation:

The kinetic energy of the wind drives wind power.

Question 16: Choose the INCORRECT statement

(a) We are encouraged to plant more trees so as to ensure a clean environment and also provide biomass fuel

(b) Biomass is a renewable source of energy

(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) Gobar-gas is produced when crops, vegetable wastes etc., decompose in the absence of oxygen

Answer 16: (c)

Explanation:

Methane is a biogas’ main byproduct. When it burns it doesn’t leave behind any ash.

Question 17: What are geothermal energy hot spots?

Answer 17:

Molten rocks that develop in the deeper, hotter layers of the earth’s crust are forced upward and trapped in some areas as a result of geological changes. Hot spots are the names for these areas.

Question 18:

Name the phenomenon that explains the working of an electric generator.

Answer 18:

The phenomenon explaining the working of an electric generator is electromagnetic induction.

Question 19:

State an important advantage of using AC over DC.

Answer 19:

AC compared to DC, AC voltages can be readily transformed to higher or lower voltage levels, while it is difficult to do that with DC voltages. It can be transmitted across long distances with little loss of electric power.

Question 20:

Name one material used to make a solar cell and also mention the range of voltage produced by a typical cell.

Answer 20:

A solar cell is made of silicon. Voltage in a normal cell ranges from 0.5 to 1 V.

Question 21:

Write the name of the substance whose vapours are used to run the turbine of the generator of the ocean thermal energy plant.

Answer 21:

Volatile liquid ammonia.

Question 22:

Name the energy obtained from sea or ocean water due to the difference in temperature at the surface and in deeper sections of these water bodies.

Answer 22:

Ocean thermal energy conversion(OTEC).

Question 23: How is hydropower harnessed?

Answer 23:

Water contained in a dam’s potential energy is transformed into the kinetic energy of water falling, which is eventually transformed into electrical energy.

Question 24: Define 1 MW.

Answer 24:

A device that consumes or dissipates 1 megajoule of energy per second is said to consume or dissipate 1 MW of power.

Question 25: Mention two disadvantages of constructing Tehri Dam.

Answer 25:

Around 100,000 people or more have been displaced in order to build the Tehri Dam, which sparked considerable unrest and legal disputes. Large ecosystems were also devastated due to the loss of biodiversity when they were submerged under the water in dams, which led to the emission of a lot of methane, a greenhouse gas.

Question 26: What happens when water from great heights is made to fall on the blades of the turbine?

Answer 26:

When water is made to fall from great heights, its potential energy is transformed into kinetic energy, which, when it strikes turbine blades, rotates a generator to produce electricity.

Question 27.

Why is biogas considered an excellent fuel?

Answer 27: Biogas is considered an excellent fuel because

• it does not produce smoke.
• Left behind slurry can be used as excellent manure.

Question 28: Name any two nutrients that the spent slurry has in the biogas plant.

Answer 28: Nitrogen and phosphorus.

Question 29: Write the energy conversion that takes place in a hydropower plant.

Answer 29: The potential energy of water that has been stored is converted into electrical energy by hydropower plants.

Question 30: Name any two fossil fuels.

Answer 30: Coal and petroleum are two fossil fuels.

Question 31: Name any two conventional sources of energy.

Answer 31:

(i) Fossil fuels (ii) Wind energy

Question 32:

What is meant by the term ‘Biomass’?

Answer 32:

Biomass: Biomass is any plant substance that can decay in the absence of oxygen, such as cow dung, other plant materials like crop residue after harvest, vegetable wastes, and sewage.

Question 33:

Write the characteristic features of the microorganisms which help in the production of biogas in a biogas plant.

Answer 33:

Anaerobic microorganisms are utilised in biogas plants. They can break down and degrade the complex molecules in the cow dung slurry without the need for oxygen.

Question 34:

What are fossil fuels? “Burning fossil fuels may lead to intense global warming.” Justify this statement.

Answer 34:

Fossil fuels: Fossil fuels are combustible materials created from dead plants and animals that have been buried deep beneath the earth’s surface for millions of years.

Carbon dioxide is produced when fossil fuels are burned, and too much of it in the atmosphere has a greenhouse effect that promotes rapid global warming.

Question 35:

What are the main components of biogas? How is biogas obtained from biomass? Write any two advantages of using this gas.

Answer 35:

Methane makes up 75% of biogas’s composition. Biomass is broken down anaerobically in a biogas plant to produce biogas. The two advantages of using biogas are

• smoke-free cooking.
• has a high calorific value.

Question 36:

Define: (i) Anaerobic degradation

Answer 36:

(i) Anaerobic degradation: Anaerobic degradation refers to the breakdown of big organic compounds into simpler ones without the presence of air.

Question 37:

Explain the process of biogas production in a biogas plant.

Answer 37:

Working of the biogas plant:

In the mixing tank, dung and home and agricultural waste are combined with water. The digester’s inlet chamber receives the slurry that was produced in this manner. Biogas is produced as anaerobic fermentation gradually takes hold. A new biogas plant must run for around 6 to 8 weeks before it can begin producing biogas at a respectable pace. The spent slurry is then forced into the outlet chamber and then into the overflow tank as the biogas pressure inside the dome rises. The used slurry is utilised as manure in agricultural fields since it is a rich source of plant nutrients.

The gas valve can be spun to remove biogas for supply. Dung slurry is then fed into the digester and periodically withdrawn from it to keep the biogas plant running constantly.

Question 38:

List any four disadvantages of using fossil fuels for the production of energy.

Answer 38:

The disadvantages of using fossil fuels for the production of energy are :

• These are non-renewable sources of energy.
• It releases pollutants into the air.
• Its formation takes millions of years
• It causes acid rain.

Question 39:

State the difference between energy obtained by burning fossil fuels and that obtained as solar energy.

Answer 39:

• The reserves of fossil fuels are finite or exhaustible, whereas the supply of solar energy is limitless and abundant or inexhaustible.
• Solar energy is pollution-free, but fossil fuels produce pollution when they are burned.
• While solar energy is unavailable when the sky is overcast, fossil fuels can supply energy whenever it is needed.

Question 40:

Define the process of nuclear fission. Write the steps involved in generating electricity in a nuclear reactor.

Answer 40:

Nuclear fission is the process by which a heavy nucleus splits into two fragments of comparable mass after being bombarded by slow-moving neutrons, along with the release of two or more fast-moving neutrons and a significant quantity of energy.

Steps involved in generating electricity:

• Slowly travelling neutrons are used to attack big atoms like uranium or plutonium.
• Lots of heat energy is released when large atoms shatter.
• Water is heated to a steamy state using this heat.
• The turbine that generates energy is rotated by this steam.