NCERT Solutions Class 8, Social Science, Geography, Chapter "Mineral and Power Resources".
1. Answer the following questions.
(i) Name any three common minerals used by you everyday.
Solution:
Salt, Gold and Copper are three common minerals used everyday
(ii) What is an ore? Where are the ores of metallic minerals generally located?
Solution:
Rocks from which minerals are mined are known as ores. For any material to be called ore of any mineral, it must contain minimum adequate quantity of that mineral so that it can be extracted profitably.
(iii) Name two regions rich in natural gas resources.
Solution:
Russia and Norway are the two regions rich in natural gas resources.
(iv) Which sources of energy would you suggest for
(a) Rural areas
(b) Coastal areas
(c) Arid regions
Solution:
(a) Biogas energy for rural areas
(b) Hydel and tidal energy for coastal areas
(c) Wind and solar energy for arid regions
(v) Give five ways in which you can save energy at home.
Solution:
Five ways in which energy can be saved at home:
Switching off lights, fans and other electrical appliances when not in use
By seeing to it that electrical devices are operating efficiently; for example, defrosting refrigerator regularly and not keeping the refrigerator door open for longer than necessary
Using energy-efficient devices such as fluorescent bulbs and tubes
Using energy efficiently while cooking; for example, keeping the lids of pans on while cooking
Unplugging electrical devices when not in use prevents leakage of electricity; thus saving energy.
2. Tick the correct answer.
(i) Which one of the following is nota characteristic of minerals?
(a) They are created by natural processes.
(b) They have a definite chemical composition.
(c) They are inexhaustible.
(d) Their distribution is uneven.
The correct option is : (c) They are inexhaustible.
(ii) Which one of the following is nota producer of mica?
(a) Jharkhand
(b) Karnataka
(c) Rajasthan
(d) Andhra Pradesh
The correct option is : (b) Karnataka
(iii) Which one of the following is a leading producer of copper in the world?
(a) Bolivia
(b) Ghana
(c) Chile
(d) Zimbabwe
The correct option is : (c) Chile
(iv) Which one of the following practises will not conserve LPG in your kitchen?
(a) Soaking the dal for some time before cooking it.
(b) Cooking food in a pressure cooker.
(c) Keeping the vegetables chopped before lighting the gas for cooking.
(d) Cooking food in an open pan kept on low flame.
The correct option is : (d) Cooking food in an open pan kept on low flame.
3. Give reasons.
(i) Environmental aspects must be carefully looked into before building huge dams.
Solution:
Dams help in creating hydroelectric power, which solves the energy problems of a region. They also help farmers as the water released from dams is used for irrigation. However, dams have a negative impact on the environment as well. They adversely affect the surrounding ecosystems by destroying the local flora and fauna, by displacing the local community, by changing the natural course of rivers, etc. Therefore, before a dam is built at a site, it should be ascertained whether its benefits justify the damages that it would inevitably cause to the various ecosystems. If they do justify, then steps should be taken to minimise the damages to the flora and fauna, and to relocate the local community. But if they don’t, then environmental conservation should be given the priority over the building of the dam.
(ii) Most industries are concentrated around coal mines.
Solution:
Coal is used as a source of energy and power and also as a raw material in most of the industries. Hence most industries are concentrated around coal mines of the purpose saving cost of transportation of coal (cost effectiveness).
(iii) Petroleum is referred to as “black gold”.
Solution:
Petroleum is referred to as “black gold” because it is black in colour in the crude form and its derivatives are extremely valuable as petroleum itself. Today it is almost inevitable in our day-to-day life. A variety of products like – kerosene, diesel, petrol, wax, plastics, lubricants etc. are produced from these mineral resources.
(iv) Quarrying can become a major environmental concern.
Solution:
Quarrying is an extraction process by which minerals lying near the Earth’s surface are dug out. This process can adversely affect the environment in different ways. The digging involves clearing of vegetation. This destroys the top soil, which contains the humus required for plant growth. The quarrying process involves the use of explosives and earth-moving equipments. These cause noise pollution, and may also damage nearby buildings, dams or other such structures. The dust generated during quarrying and the fossil fuels burnt while operating the equipments contribute to air pollution, which in turn affects the health of the miners and the local population.
4. Distinguish between the following.
(i) Conventional and non-conventional sources of energy
Solution:
| Conventional sources of energy |
Non-conventional sources of energy |
| Have been in common use for a long time |
Are not commonly used |
| Are generally exhaustible |
Are generally inexhaustible |
| Are mostly polluting |
Are mostly non-polluting |
| Example: Firewood, coal |
Example: Solar energy, nuclear energy |
