Question

Name alternate sources of energy and describe the principles on which they operate.

Answer 1

Alternate sources of energy include all sources of energy other than fossil fuels and includes all the renewable and nuclear energy sources.

Some of the alternate energy sources are

1. Solar energy
2. Wind power
3. Hydropower
4. Biofuel
5. Geothermal energy
6. Nuclear power

Solar Energy-

1. Solar energy is harnessed with the help of solar cookers, solar heaters, and solar cells. Solar cells work on the principle of the photovoltaic effect.
2. When they are exposed to sunlight they absorb photons and release free electrons. That means they directly convert sunlight into electricity.
3. Solar cookers and solar heaters directly use the heat energy of sunlight light for cooking and heating purposes.

Wind power-

1. Wind power is also used to produce electricity. The blowing wind possesses a large momentum and exerts a large force on the body on which it strikes.
2. It works on the principle of conversion of the kinetic energy of blowing wind into electricity. When blowing wind strikes the blades of a windmill it rotates which will turn the shaft which is connected to a generator.
3. This makes the generator produce electricity.

Hydropower-

1. Here the potential energy of water is converted into rotational kinetic energy of the turbine.
2. The turbine then converts the kinetic energy into mechanical energy and the generator converts mechanical energy into electrical energy.

Biofuel-

1. Biofuel is a fuel produced from biomass over a short period.
2. There are various ways of making biofuels but they generally use chemical reactions, fermentation, and heat to break down the starches, sugar, and other molecules in plants. To produce biofuel, biomass is harvested and transported for threshing.
3. Later the cellulose obtained from the residues left after threshing is converted to glucose. The glucose is further converted to liquid fuel through fermentation, which is used for various purposes.

Geothermal energy-

1. This is the energy stored inside the earth's crust. Hot rocks in the core of the earth emit steam with high temperatures and pressure.
2. Geothermal energy is extracted from the earth through the dry steam technique. This steam is used to turn a turbine and produce electricity.

Nuclear power-

1. Nuclear energy is used to produce electricity with the help of the heat energy produced during the nuclear fission reaction. The common nuclear fuels used are uranium and plutonium.