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Energy from various sources is considered to have been derived from the sun. Do you agree? Justify your answer.

Answer: Energy from various sources is considered to have been derived from the sun. The following points can justify the statement. Energy from... View Article

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 substances which act as energy sources are known as fuels. The buried organic matters which can be converted to crude oil, coal,... View Article

Why is there a need for harnessing non-conventional sources of energy? How can energy be harnessed from the sea in different ways?

Answer: Non-conventional sources of energy are also known as renewable sources of energy. They are also known as renewable sources of energy and... View Article

Make a list of conventional and non-conventional sources of energy. Give a brief description of harnessing one nonconventional source of energy.

Answer: Conventional sources of energy are coal, petroleum, firewood and tidal energy. Non-conventional sources are Solar energy, nuclear energy,... View Article

How can solar energy be harnessed? Mention any two limitations in using solar energy. How are these limitations overcome?

Answer: Solar energy can be directly harnessed through the use of a solar cooker, a solar heater, or solar cells. A solar cooker is defined as... View Article

Which is the process used to harness nuclear energy these days? Explain it briefly.

Answer: Nuclear fission and fusion are two ways to harness nuclear energy. The nuclear fission process is used to harness nuclear energy these... View Article

What are the limitations in obtaining energy from wind?

Answer: The term wind energy is a system of components that converts the kinetic energy of the wind into electricity or mechanical power, and... View Article

What is biomass? What can be done to obtain bio-energy using biomass?

Answer: Biomass is defined as the fuel made from organic matter or wastes of living organisms that can be used as renewable sources of energy.... View Article

Mention three advantages of a solar cell?

Answer: A solar cell is a device that directly converts the energy of light into electrical energy through the photovoltaic effect. Solar cells... View Article

What is the role of a plane mirror and a glass sheet in a solar cooker?

Answer: A plane mirror reflects the sunlight thereby increasing the intensity of solar energy. Glass sheet prevents heat to escape from the solar... View Article

What steps would you suggest to minimise environmental pollution caused by the burning of fossil fuels?

Answer: The substances which act as energy sources are known as fuels. The buried organic matters which can be converted to crude oil, coal,... View Article

Write two different ways of harnessing energy from the ocean.

Answer: The two different ways of harnessing energy from the ocean are Tidal wave and Ocean Thermal Energy Conversion (OTEC). The level of... View Article

Why is there a need to harness non-conventional sources of energy? Give two main reasons.

Answer: Non-conventional sources of energy are also known as renewable sources of energy. They are also known as renewable sources of energy and... View Article

Choose the incorrect statement (a) We are encouraged to plant more trees so as to ensure a 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) Biomass is a renewable source of energy

Answer: (c) The main ingredient of bio-gas is ethane and it gives a lot of smoke and also produces a lot of residual ash The main product of... View Article

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: (b) The potential energy content of wind blowing at high altitudes is the source of wind power Wind power is the conversion of wind... View Article

In a hydroelectric power plant, more electrical power can be generated if waterfalls 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: (b) a larger amount of potential energy is converted into kinetic energy Hydroelectric power plants convert the potential energy of... View Article

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: (a) Sun can be taken as an inexhaustible source of energy Fossil fuel is an exhaustible source. Hydro and wind energy plants can have... View Article

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: (c) depends on wind velocity A windmill is defined as a machine that converts the kinetic energy of the wind into mechanical energy. Wind... View Article

The main constituent of biogas is (a) methane (b) carbon dioxide (c) hydrogen (d) hydrogen sulphide

Answer: (a) methane Biogas is a renewable energy source produced by the breakdown of organic matter by certain bacteria under anaerobic... View Article

Which part of the solar cooker is responsible for the greenhouse effect? (a) Coating with black colour inside the box (b) Mirror (c) Glass sheet (d) Outer cover of the solar cooker

Answer: (c) Glass sheet The greenhouse effect is the process by which radiations from the sun are absorbed by the greenhouse gases and not... View Article

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