Question 1

Question 1(c)Give a reason for each of the following:(i) Non-conventional sources of energy are called the resources of the future.(ii) India is an advantageous position in terms of solar energy.(iii) Harvesting of solar energy does not require much maintenance.

Accepted Answer

(i) Non-conventional sources of energy are called the resources of the future as most of these sources of energy are renewable, non-polluting, less expensive to run and easy to maintain.(ii) India in an advantageous position to harness solar energy because of India's location on the Tropic of Cancer. Most parts of the country have 300 clear sunny days in a year and per hour per square km availability of solar energy between 5 to 7 kW.(iii) Harvesting of solar energy does not require much maintenance as most reliable solar panel manufacturers give 20-25 years warranty. Also, as there are no moving parts, there is no wear and tear. So, after covering the initial cost of the solar energy system, it requires very little spending on maintenance and repair work.

Question 2

Question 1(d)How is India in an advantageous position to harness solar energy?

Accepted Answer

India is in an advantageous position to harness solar energy because of India's location on the Tropic of Cancer. Most parts of the country have 300 clear sunny days in a year and per hour per square km availability of solar energy between 5 to 7 kW.

Question 3

Question 2(a)State briefly how the Sun's energy can be used to generate power.

Accepted Answer

Sun's energy can be transformed into electrical energy with the help of solar cells. Solar cells are also known as photovoltaic cells. They are made up of thin wafers of semi conductor materials from silicon and gallium. When Sun's light falls on them, the Sun's energy gets converted into electricity.

Question 4

Question 2(b)How can wind energy generate additional income for the land owners?

Accepted Answer

Land owners can look for additional income by installing wind turbines on land that can even be used for agricultural purposes. The electricity generated by wind power can be used for domestic consumption and reduce monthly electricity bills, and the surplus power can be sold back to the local grid which can result in more savings. Hence, wind energy can generate additional income for the land owners.

Question 5

Question 2(c)State any three advantages of using solar energy.

Accepted Answer

Three advantages of using solar energy are-It is a renewable source of energy which can be harnessed in most of the areas of the world.It can be used for diverse purposes like producing electricity in areas without access to the energy grid, to distill water in regions with limited clean water supplies and to power satellites in space.Solar energy systems do not require a lot of maintenance.

Question 6

Question 2(d)How is wind energy utilised to produce electricity?

Accepted Answer

The wind energy is obtained by making use of windmills. The blades of the windmill rotate due to the force of the wind. The rotational motion of the blades drives a number of machines like water pumps, flour mills and electric generators. A number of windmills are installed in a definite pattern in clusters called wind farms. They generate a large amount of electricity.

Question 7

Question 3(a)What is tidal energy? Give an advantage of using tidal energy.

Accepted Answer

The rise and fall of water of the ocean produced by the attraction of the Moon and Sun produces a large amount of energy called Tidal energy.An advantage of Tidal energy is that it can be produced even if the water moves at a low speed.

Question 8

Question 3(b)Give two advantages of using wind energy.

Accepted Answer

Two advantages of using wind energy are-It is a renewable source of energy that can be produced again and again.It is the cleanest form of renewable energy that produces no pollution.

Question 9

Question 3(c)What are wind farms? Where are they usually located?

Accepted Answer

A number of windmills are installed in a definite pattern in clusters called wind farms.They are usually installed in coastal regions, open grasslands or hilly regions.

Question 10

Question 3(d)(i) What is geothermal energy?(ii) How is geothermal energy used to produce electricity?

Accepted Answer

(i) Geothermal energy is the heat energy contained in the rock and fluid that fills the fractures and pores within the rock in the earth's crust.(ii) Resources of geothermal energy can be generated by using the shallow steam, hot water and hot rock by drilling wells up to thousands of feet beneath the earth's surface. The extremely high temperatures in the deeper geothermal reservoirs are used for the generation of electricity. The high-pressure steam spins the turbine that rotates a generator and produces electricity.Hot water is pumped from deep underground through a well under high pressure. When the water reaches the surface, the pressure is dropped, which causes the water to turn into steam. The steam spins the turbine, which is connected to a generator that produces electricity. The steam cools off in the cooling tower and condenses back to water. The cooled water is pumped back into the earth to begin the process again.

Question 11

Question 4(a)Name one area each where solar, wind, tidal and geothermal energy is generated in India.

Accepted Answer

EnergyAreaSolar energyBhadla Solar Park, Jodhpur, RajasthanWind energyMadurai in Tamil NaduTidal energyGulf of KutchGeothermal energyManikaran in Himachal Pradesh

Question 12

Question 4(b)State any two advantages of using geothermal energy.

Accepted Answer

Two advantages of using geothermal energy are-It is easily accessible because of its extensive distribution.It is independent of weather and season.

Question 13

Question 4(c)Name the process involved in generation of nuclear energy. State any three advantages of using nuclear power.

Accepted Answer

The process involved in generation of nuclear energy is known as Nuclear Fission.Three advantages of using nuclear power are —Nuclear energy reduces the requirement of the amount of energy generated from fossil fuels and therefore, reduces the use of fossil fuels and lowers Greenhouse Gas emissions.Fission of one atom of uranium produces ten million times the energy released by burning of one atom of carbon. In this way, nuclear energy not only saves on raw materials but also in transport, handling and extraction of nuclear fuel. The cost of nuclear fuel is 20% of the cost of energy generated.Nuclear energy is the most reliable source of energy as nuclear power plants can run 24 hours a day and seven days a week.

Question 14

Question 4(d)How is biogas beneficial for the farmers and householders?

Accepted Answer

Biogas is beneficial for the farmers in the form of energy and good quality manure. It is useful for the householders as the gas is used for cooking, lighting and pumping water from wells.

Question 15

Question 5(a)What is nuclear power?

Accepted Answer

Nuclear power is obtained from energy stored in the nuclei of atoms of naturally occurring radioactive elements like uranium, thorium and plutonium.

Question 16

Question 5(b)Name two minerals used for the generation of nuclear energy. Name two nuclear power plants in India.

Accepted Answer

Uranium and Thorium are the two minerals used for the generation of nuclear energy.Two nuclear power plants in India are-Kaiga in KarnatakaKakrapar in Gujarat

Question 17

Question 5(c)Raw material for nuclear power are minerals that are non-renewable. But countries prefer it to conventional energy sources. Why?

Accepted Answer

Countries prefer nuclear power over conventional energy sources because it produces a large amount of energy from a small amount of fuel and does not emit harmful greenhouse gases. Even though the raw materials like uranium are non-renewable, nuclear power helps reduce air pollution and dependence on fossil fuels. It is a more efficient and cleaner energy option, making it attractive for meeting growing energy needs while protecting the environment.

Question 18

Question 5(d)Explain how using nuclear energy in a controlled environment can be a boon for our country.

Accepted Answer

Using nuclear energy in a controlled environment can be a boon for our country for the following reasons-Nuclear energy reduces the requirement of the amount of energy generated from fossil fuels and therefore, reduces the use of fossil fuels and lowers Greenhouse Gas emissions.Fission of one atom of uranium produces ten million times the energy released by burning of one atom of carbon. In this way, nuclear energy not only saves on raw materials but also in transport, handling and extraction of nuclear fuel. The cost of nuclear fuel is 20% of the cost of energy generated.Nuclear energy is the most reliable source of energy as nuclear power plants can run 24 hours a day and seven days a week. Besides, a nuclear plant needs to refuel every 18 to 24 months. This shows that nuclear fuels are less affected by fluctuating fuel prices than the more volatile industries like oil and natural gas.When compared to the fossil fuel waste, the nuclear waste which occurs due to the production of nuclear power is small in quantity.

Question 19

Question 6(a)Figure 1 is a picture of a biogas plant. Briefly explain how biogas is generated.

Accepted Answer

Biogas is produced by the anaerobic decomposition of animal and plant waste in the presence of water. In this oxygen-free environment, bacteria break down the waste and release methane-rich gas. The mixture is fed into an underground digester tank through an inlet pipe. As bacteria ferment the waste, biogas is collected through a gas outlet, while the leftover slurry is removed via an outlet pipe.

Question 20

Question 6(b)Name the main constituents of biogas.

Accepted Answer

The main constituents of Biogas are:MethaneCarbon dioxideHydrogenHydrogen sulphide

Non-Conventional Sources of Energy

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