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Saturday, May 23, 2020

Mineral and Power Resources | Chapter 3 | Geography 8th |

Book Cover Social Science Geography Class 8th


Mineral and Power Resources | Chapter 3 | Geography 8th |

Chapter 3 – Mineral and Power Resources

 Exercises

Free Download | Geography | Class 8th | eBook |

Q1.   Answer the following questions.

(i) Name any three common minerals used by you every day.

Ans. Three common minerals used every day:

(a) Copper, Electric wires
(b) Talc, Talcum powder
(c) Lead, Batteries

(ii) What is an ore? Where are the ores of metallic minerals generally located?

Ans. Ores are the rocks from which minerals are mined. The ores of metallic minerals are generally found in igneous and metamorphic rock formations that form large plateaus.

(iii) Name two regions rich in natural gas resources.

Ans. Russia and the United Kingdom 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

Ans.

(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.

Ans. Five ways in which energy can be saved at home:
(a) Switching off lights, fans and other electrical appliances when not in use.
(b) 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.
(c) Using energy-efficient devices such as fluorescent bulbs and tubes
(d) Using energy efficiently while cooking; for example, keeping the lids of pans on while cooking.
(e) Unplugging electrical devices when not in use prevents leakage of electricity; thus saving energy.

Q2. 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.

(ii) Which one of the following is a leading producer of copper in the world?

(a) Bolivia (c) Chile

(b) Ghana (d) Zimbabwe

(iii) 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.

(i). Which one of the following is not a characteristic of minerals?

Ans. (c) They are inexhaustible

(ii). Which one of the following is not a producer of mica?

Ans. (b) Karnataka

(iii). Which one of the following is the leading producer of copper in the world?

Ans. (c) Chile

(iv). Which one of the following practices will not conserve LPG in your kitchen?

Ans. (d) Cooking food in an open pan kept on low flame.

Q3. Give reasons – Why?

(i) Environmental aspects must be carefully looked into before building huge dams;

Ans. 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 minimize the damages to the flora and fauna, and to relocate the local community. But if they don’t, then environmental conservation should be given priority over the building of the dam.

(ii) Most industries are concentrated around coal mines.

Ans. Coal is the most abundant fossil fuel. It is widely used as a source of energy. It is also used as a raw material in several industries. Most industries are located around coal mines as being situated close to coal mines proves to be cost-effective. Coal can easily be transported from the mines to the industries, and this reduces both time and cost of transportation.

(iii) Petroleum is referred to as “black gold”?

Ans. The term “black gold” is used with reference to petroleum and its various derivatives. The word ‘black’ refers to the colour of petroleum in its crude form. The word ‘gold’ implies that petroleum and all the various products of petroleum (like diesel, petrol, kerosene, wax, plastics, and lubricants) are as valuable to human society as the metal gold.

(iv) Quarrying can become a major environmental concern.

Ans. Quarrying is an extraction process by which minerals lying near the Earth’s surface is the dugout. This process can adversely affect the environment in different ways. The digging involves clearing of vegetation. This destroys the topsoil, which contains the humus required for plant growth. The quarrying process involves the use of explosives and earth-moving equipment. 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 equipment contribute to air pollution, which in turn affects the health of the miners and the local population.

Q4. Distinguish between the following:

(i) Conventional and non-conventional sources of energy

(ii) Biogas and natural gas

(iii) Ferrous and nonferrous minerals

(iv) Metallic and non-metallic minerals

Ans.

(i) Conventional and non-conventional sources of energy:

 

Conventional

Non-conventional

(i) Have been in common use for a long time.

(i). Are not commonly used.

(ii) Are generally exhaustible.

(ii) Are generally inexhaustible.

(iii) Are mostly polluting.

(iii) Are mostly non-polluting.

(iv) Example; Firewood, coal

(iv) Example; Solar energy, nuclear energy.

 Ans.

(ii) Biogas and natural gas:

 

Biogas

Natural Gas

i. Found using organic wastes, such as dead plants and animal matter, etc.

i. Found along with petroleum deposits and gets released when crude is brought to the surface.

ii. It is a non-conventional source of energy.

ii. It is a convenient source of energy.

iii. It is easily available, especially in rural areas.

iii. It is not easily available, very few countries have natural gas reserves.

iv. Is polluting, causes the greenhouse effect by releasing carbon dioxide.

iv. It is a cleaner fuel.

v. Used as a domestic fuel as cooking and lighting.

v. Used as domestic fuel and industrial fuel.

 

Ans.

(iii) Ferrous and non-ferrous minerals:

 

Ferrous

Non-ferrous

i. A metallic mineral that contains iron.

i. A metallic mineral that does not contains iron.

ii. Example: Iron ore, manganese.

ii. Example: Gold, silver.

 

Ans.

(iv) Metallic and non-metallic minerals:

 

Metallic

Non-metallic

i. A mineral containing metal in raw form.

i. A mineral not containing metal.

ii. Example: Bauxite, iron ore.

ii. Example: Limestone, gypsum.

 


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