Non-conventional sources of energy are as follows:
(i) Solar energy: Solar energy, trapped from the sun, can be used in solar cells to produce electricity. Solar energy is used in solar cooker, solar heaters and solar dryers.
(ii) Wind energy : Energy obtained from high speed wind is called wind energy. The high speed wind rotates the wind mill which is connected to a generator to produce electricity
(iii) Geothermal Energy : Heat energy obtained from earth is called Geothermal energy. Geothermal energy in the form of hot springs has been used for cooking, heating and bathing.

(i) The Canadian region north of the Great lakes.
(ii) The Appalachian Region.
(iii) The mountain ranges of the west.

India has a bright future in nuclear energy for the following reasons :
(i)The nuclear energy is produced from radioactive elements such as Uranium and Thorium.
(ii) These elements, Uranium and Thorium, undergo nuclear fission in nuclear reactors and emit lots of energy and power.
(iii) In India, sufficient quantities of Uranium is available in Rajasthan and Jharkhand and Thorium in Kerala.

Mining is the process of digging out the minerals which are buried under the interior layers of earth. There are two types of mining. These are:
(i) Open Cast Mining : This type of mining is used for the shallow depth minerals.
(ii) Shaft Mining: This type of mining is used to obtain deep depth mineral deposits.

Minerals can be identified on the following basis:
(i) Physical Properties :
1.Density
2.Colour
3. Hardness 2
(ii) Chemical Properties:
1. Solubility

Coal, mineral oil and natural gas are called fossil fuels because:
(i) They are organic by origin.
(ii) They are produced from the plant and animal remains as they have been buried in earth for a long period of time.
(iii) They are a part of fossils, therefore they are called fossil fuels.

The process of Hydel Power Generation is as under:
(i) The stored river water in the dams is made to fall over the blades of the turbines through the pipelines.
(ii) This falling water helps to rotate the blades that start the generator attached to the turbine.
(iii) The energy generated through this process is called Hydel energy.

The various non-conventional energy sources are:
(i) Wind energy.
(ii) Solar energy.
(iii) Tidal energy.
(iv) Nuclear energy.
(v) Bio gas.
(vi) Geothermal energy.

The use of non-conventional sources of energy is becoming necessary because:
The growing consumption of energy in the country has made us dependent on fossil fuels such as coal, oil and gas.
Rising prices of oil and gas have eroded our foreign currency reserves.
Shortages in the supply of oil, gas and coal have increased uncertainties about the security of energy supply in future

The alternative power sources apart from coal energy and hydroelectric energy are solar energy wind energy, tidal energy, nuclear energy and geothermal energy.
They are found in nature free of cost. The proper techniques are used to harness these renewable sources of energy. They are very useful since they are non-exhaustible and pollution-free energy sources. They are considered future source of energy.

Minerals and energy resources can be preserved in the following ways:
1. By using solar, hydroelectric and other renewable forms of energy and recycling minerals
2. Export of strategic and scarce mineral must be reduced, so that the existing reserve may be used for a longer period.  
3. Development of alternative energy source like solar power, wind, wave, geothermal energy must be encouraged to replace the exhaustible resources

Organic wastes like dead plant and animal material, animal dung and kitchen waste can be converted into a gaseous fuel called biogas. The organic waste is decomposed by bacteria in biogas digesters to emit biogas.
It is a mixture of carbon dioxide and methane. Biogas is an excellent fuel for cooking and lighting. Moreover, biogas plants produce a huge amount of manure each year

Environmental aspects must be carefully looked into before building huge dams because of the following reasons:
(a) Dams create imbalance in the Earth's equilibrium. Deforestation leads to environmental pollution.
(b) People become displaced.
(c) Flood threats loom large.

Iron, salt, copper.