Mineral and Power Resources Extra Questions Chapter 3 Class 8 Geography
Chapter 3 Mineral and Power Resources Extra Questions for Class 8 Geography will be helpful in understanding the key concepts of the chapter properly. Through the help of Class 8 Extra Questions, you will prepare for the examinations in a better manner.
Chapter 3 Mineral and Power Resources Very Short Answer Questions (VSAQs):
1. In which industry is silicon important? From which ore is it obtained?
Answer
Silicon is important in the computer industry which is obtained from quartz.
2. Differentiate between a rock and an ore.
Answer
A rock is an aggregate of one or more minerals. An ore is a rock from which minerals are mined.
3. Name two areas in Australia, which have large deposits of gold.
Answer
Two areas in Western Australia having large deposits of gold are Kalgoorlie and Coolgardie.
4. How can minerals be identified?
Answer
Minerals can be identified on the basis of their physical properties such as colour,\ density, hardness and chemical property such as solubility.
5. Define quarrying.
Answer
Quarrying is a process of extraction in which minerals lying near the surface are simply dug out.
6. Why is coal called “buried sunshine”?
Answer
Coal is called “buried sunshine” because it is found buried under the earth, and is as important a source of energy as sunshine.
7. Why do we need power resources?
Answer
We need power or energy resources for industry, agriculture transport, communication and defense.
8. Why are minerals considered non-renewable?
Answer
Minerals take thousands of years to form. The rate of formation is much smaller than rate of consumption. So we classify them as non-renewable.
9. Which was the first country to develop hydroelectricity ?
Answer
Norway was the first country to develop hydroelectricity.
10. Why are petroleum and its derivatives called “black gold”?
Answer
Petroleum and its derivatives are black in colour but as valuable as gold, so we refer to it as “black gold”.
11. Give one advantage of biogas over natural gas.
Answer
Biogas is a renewable source of energy whereas the amount of natural gas is limited.
12. Where are the ores of metallic minerals generally located?
Answer
Ores of metallic minerals are located in igneous and metamorphic rock formations that form large plateaus.
Chapter 3 Mineral and Power Resources Short Answer Questions (SAQs):
1. What are the advantages and disadvantages of firewood?
Answer
Advantages of firewood:
• It is easily accessible.
• It provides energy to a large number of people.
Disadvantages of firewood:
• The collection of firewood is time consuming.
• It leaves polluting effects on the surroundings.
• It promotes greenhouse effect.
• It encourages deforestation.
2. Where are minerals found?
Answer
Minerals are located in different types of rocks. Some are found in igneous rocks, some in metamorphic
rocks while others occur in sedimentary rocks.
• Metallic minerals are generally located in igneous and metamophic rock formations that form large plateaus. Iron ore in North Sweden; copper and nickel deposits in Ontario, Canada; iron, chromites and platinum in South Africa are examples of minerals found in igneous and metamorphic rocks.
• Non-metallic minerals such as limestone are located in sedimentary rock formation of plains and young fold mountains. Limestone deposits of Caucasus region of France, manganese deposits of Georgia, etc. are some examples.
• Coal and petroleum are also found in sedimentary strata.
3. How is hydroelectricity produced?
Answer
Hydroelectricity is produced from the energy possessed by water falling from great heights. River water is stored in dams. When rain water or river water falls from heights, it flows over turbine blades placed at the bottom of the dam. The moving blades are connected to a generator which produces electricity from this energy. This electricity is called hydroelectricity. The water discharged after its production is used for irrigation.
4. Classify minerals on the basis of composition.
Answer
On the basis of composition, minerals are classified as:
(i) Metallic minerals: These minerals contain metal in raw form. For example, iron ore, bauxite, manganese ore. Metallic minerals may be ferrous or non-ferrous. Ferrous minerals contain iron. For example iron ore, manganese and chromites. A non-ferrous mineral does not contain iron but may contain some other metal such as gold, silver, copper or lead.
(ii) Non-metallic minerals: These minerals do not contain metals. For example, limestone, mica and gypsum. Coal and petroleum are also non-metallic minerals.
5. Name and describe briefly methods of extraction.
Answer
Mining, drilling and quarrying are methods of extraction. Mining is a process of extraction of taking out minerals from rocks under the earth’s surface.
• Open cast mining: In this, minerals lying at shallow depths are taken out by removing the surface layer.
• Shaft mining: In this, deep bores (called shafts) are made to reach mineral deposits lying at large depths. Drilling: In this, deep wells are bored to take out minerals.
• Quarrying: It is the process of extraction in which minerals lying very close to the surface are extracted just by digging them out.
6. Describe the mineral distribution in North America.
Answer
The mineral deposits in North America are found in three zones: the Canadian region in the north of the Great Lakes, the Appalachian region and the Rocky Mountains in the West. Iron ore, nickel, gold, uranium and copper are mined in the Canadian Shield Region, coal in the Appalachian region. Western Cordilleras have vast deposits of copper, lead, zinc, gold and silver.
7. Describe some common uses of minerals.
Answer
Minerals are important in many industries. Minerals used in gems are usually very hard. These are then set in varying styles of jewellery. Iron and copper are metals used in almost everything. Copper is present in everything from coins to pipes and electricity wires. Silicon, obtained from the mineral quartz, is the base of computer industry. Aluminium, obtained from bauxite ore, and its alloys are used in aeroplanes due to their light weight. Aluminium is also used in kitchen cookware.
8. What are the advantages and disadvantages of wind energy?
Answer
Advantages of wind energy:
• It is non-polluting.
• Low-cost production of electricity is possible once it is set up.
Disadvantages of wind energy:
• It creates noise pollution.
• Setting up windmills is a costly affair.
• It disturbs radio and T.V. reception.
• Wind energy is harmful to birds.
Chapter 3 Mineral and Power Resources Long Answer Questions (LAQs):
1. Write the advantages and disadvantages of non-conventional sources of energy.
Answer
Advantages of non-conventional sources of energy:
• Non-conventional sources of energy are usually inexhaustible. They do not pollute the environment.
• Nuclear power is emitted in large amounts.
• Most non-conventional sources of energy cost less.
• These forms of energy are safe to use and clean.
Disadvantages of non-conventional sources of energy:
• Wind mills are costly to set up. So using them to harness wind energy is costly, even though the electricity generated from it is cheap.
• Setting up windmills disturbs radio and TV broadcast.
• Harnessing tidal energy destroys natural habitats of wildlife.
• Moreover, tidal energy is difficult to harness.
• Obtaining nuclear energy from radioactive material generates radioactive waste. It is expensive too.
• Biogas, although useful and renewable, contributes to greenhouse effect.
2. Name and describe some non-conventional sources of energy.
Answer
Non-conventional power sources are those power sources that have come into use recently due to the depleting conventional resources and growing awareness. Solar energy, wind energy, geothermal energy, nuclear power and tidal energy are examples of non- conventional power sources.
• Solar energy is the heat and light energy captured from the sun. Solar cells help to convert this energy to electricity. Solar energy is used in solar heaters, solar cookers, solar dryers, etc.
• Wind energy is the energy possessed by moving air (wind). Windmills are used to convert wind energy to electricity. Wind farms having clusters of windmills located in coastal regions and mountain passes.
• Nuclear power is energy possessed by the nuclei of atoms of naturally occurring radioactive elements like uranium-, thorium, etc.
• Geothermal energy is the heat energy obtained from the inside of the earth. The temperature inside the earth increases as we go deeper. This heat is used to produce electricity. It is accessed in the form of hot springs.
• Tidal energy is the energy generated from tides. It is harnessed by building dams at narrow openings of the sea.
• Biogas is a gaseous fuel obtained from the decomposition of organic waste like dead plant and animal material or animal dung and kitchen waste. It is an excellent fuel for cooking and lighting, and is environment-friendly.
3. Name and describe some conventional sources of energy.
Answer
Conventional sources of energy are:
• Firewood: It is widely used for cooking and heating in villages.
• Coal: It is used as a domestic fuel, in industries and to generate electricity. Electricity from coal is called thermal power. The coal producing areas of India are Raniganj, Jharia, Dhanbad and Bokaro in Jharkhand.
• Petroleum: It is found between the layers of rocks and is drilled from oil- fields located in off-shore and coastal areas. This is then sent to refineries which process the crude oil and produce diesel, petrol, kerosene wax, plastics and lubricants. The leading petroleum producers in India are Digboi in Assam, Bombay High in Mumbai and the deltas of Krishna and Godavari rivers.
• Natural Gas: It is found with petroleum deposits and is released when crude oil is brought to the surface. It can be used as a domestic and industrial fuel. In India, Jaisalmer, Krishna- Godavari delta, Tripura and some areas such as offshore in Mumbai have natural gas resources.
• Hydel Power: Hydro electricity is generated by fast flowing water. It is a renewable resource. One-fourth of the world’s electricity is produced by hydel power. Some important hydel power stations in India are Bhakra Nangal, Gandhi Sagar, Nagarjunasagar and Damodar valley projects.