NCERT Solutions for CBSE Class 8 Social Science Chapter 25 – Free PDF Download

Free PDF download of NCERT Solutions Social Science Class 8 Solutions Chapter 25 – Mineral and Power Resources solved by Expert Social Science Teachers on CoolGyan.Org. All Chapter 25 – Mineral and Power Resources Questions with Solutions for NCERT to help you to revise complete Syllabus and Score More marks.
Science Revision Notes for Class 8

NCERT SOLVED

1. Answer the following questions.
(i) Name any three common minerals used by you every day.
Ans: The three common minerals used every day are Salt, Gold and Copper.

(ii) What is an ore? Where are the ores of metallic minerals generally located?
Ans: Rocks from which minerals are obtained are known as ores. For any material to be called ore of any mineral, it must contain a minimum adequate quantity of that mineral so that it can be extracted profitably.
The ores of metallic minerals are generally located in igneous rocks and metamorphic rocks.

(iii) Name two regions rich in natural gas resources.
Ans: The two regions rich in natural gas resources are Russia and Norway.

(iv) Which sources of energy would you suggest for rural areas (b) coastal areas (c) Arid regions?
Ans:

(v) Give five ways in which you can save energy at home.
Ans: Five ways in which energy can be saved at home:
(i) Switching off lights, fans and other electrical appliances when not in use
(ii) 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
(iii) Using energy-efficient devices such as fluorescent bulbs and tubes
(iv) Using energy efficiently while cooking; for example, keeping the lids closed, while cooking
(v) 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 NOT a 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.
Ans: (c) They are inexhaustible.

(ii) Which one of the following is NOT a producer of mica?
(a) Jharkhand (b) Karnataka (c) Rajasthan (d) Andhra Pradesh
Ans: (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
Ans: (c) Chile.

(iv) Which one of the following practices 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.
Ans: (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.
Ans: Environmental aspects must be carefully looked into before building huge dams because of the following reasons –

1. Dams create an imbalance in the earth’s equilibrium.
2. Deforestation leads to environmental pollution.
3. People become displaced.
4. Cities/ villages/ towns may require shifting causing a lot of hardships for the people.
5. Flood threats loom large.
6. Earthquake threats
7. Silting of lakes is a problem

(ii) Most industries are concentrated around coal mines.
Ans: 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 for the purpose of saving cost of transportation of coal (cost effectiveness).

(iii) Petroleum is referred to as “black gold”.
Ans: 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.
Ans: Quarrying can become a major environmental concern because of the following reasons:

1. It may destroy the humus of soil which is much required for the growth of plants and crops.
2. It produces a lot of noise pollution due to use of explosives at times in order to break the huge chunks of rocks.
3. In the process of quarrying lot of dust is generated which causes air pollution and also occupational hazards.
4. Blasting done for the purpose of quarrying generate vibration which damages the nearby buildings, dams or any other similar structure.

4. Distinguish between the followings.
(i) Conventional and Non-conventional sources of energy

(ii) Biogas and natural gas

(iii) Ferrous and Non-ferrous minerals

(iv) Metallic and Non-metallic minerals