Notes And Questions For NCERT Class 10 Social Science Minerals and Energy Resources

Students can refer to Notes And Questions For NCERT Class 10 Social Science Minerals and Energy Resources below designed as per the latest syllabus and examination patter for CBSE Class 10 Social Science

Mineral Resources

Facts that Matter

1. The earth’s crust is made up of different minerals found in the rocks and they are extracted by proper refinement. Minerals are an essential part of our lives. The hardest mineral is diamond and the softest is talc. Minerals can be defined as a homogenous, naturally occurring substance with a definable internal structure.

2. Minerals are usually found in “ores”. Ore means an accumulation of any mineral mixed with other elements. Minerals are classified on the basis of a wide range of colours, hardness, crystal forms, lustre and density that a particular mineral possesses.

3. Rocks are combinations of homogenous substances called minerals. Some rocks, for instance, limestone, consist of a single mineral only, but majority of the rocks consist of several minerals in varying proportions.

4. Classification of minerals—metallic, non-metallic and energy minerals. Metallic minerals are of three types—Ferrous (containing iron), Non-ferrous (copper, lead, etc.) and precious (gold, silver, etc.). Examples of non-minerals are—mica, salt, potash, etc. Energy minerals are coal, petroleum and natural gas.

5. Minerals occur in the veins and the lodes in igneous and metamorphic rocks. For instance, tin, copper, zinc and lead etc. are obtained from these veins and lodes. They also occur in layers in sedimentary rocks. Coal and some forms of iron ore are found in it. Minerals such as gypsum, potash, salt and sodium salt are formed with the help of evaporation especially in dry regions. Bauxite is found in the decomposed surface rocks.

6. Minerals which do not erode by water are found in Alluvial deposits. For example, gold, silver, tin and platinum.

7. The ocean waters contain vast quantities of minerals. Common salt, magnesium and bromine are largely derived from ocean waters. The ocean belts, too, are rich in manganese nodules.

8. India is fortunate to have fairly rich and varied mineral resources. Peninsular rocks contains most of the reserves of coal, metallic minerals, mica and many other non-metallic minerals. In the sedimentary rocks of Gujarat and Assam most of the petroleum deposits are found. Rajasthan with the rock systems of the peninsula, has reserves of many non-ferrous minerals.

9. Ferrous minerals account for about three-fourths of the total value of the production of metallic minerals. Iron ore, manganese, nichel and cobalt are important ferrous minerals.

10. Iron ore is the basic mineral and the backbone of industrial development. Iron ores are of two types—Magnetite and Hematite. Magnetite is the finest iron ore with a high content of iron upto 70%. Hematite ore has a slightly lower iron content than magnetite (50–60%). Iron ore is found in states like Karnataka, Odisha, Chhattisgarh, Goa and Jharkhand.

11. The four major iron ore belts are—Odisha-Jharkhand belt, Durg-Bastar-Chandrapur belt, Bellary-Chitradurga-Chikmaglur-Tumkur belt and Maharashtra-Goa belt.

12. Manganese is mainly used in the manufacturing of steel and ferro-manganese alloy. Nearly 10 kg of manganese is required to manufacture one tonne of steel. It is also used in manufacturing bleaching powder, insecticides and paints.

13. India’s reserves and production of non-ferrous minerals is not very satisfactory.

14. Being malleable, ductile and a good conductor, copper is mainly used in electrical cables, electronics and chemical industries. India is critically deficient in the reserve and production
of copper. Copper producing states are Madhya Pradesh, Jharkhand and Rajasthan.

15. Bauxite deposits are formed by decomposition of rocks rich in aluminium silicates. It is a clay-like substance from which aluminium is obtained. Aluminium is an important metal because it combines the strength of metals such as iron, with extreme lightness and also with good conductivity and great malleability. It is used in electrical industries, aircraft manufacturing industries, utensil making, etc. Orissa is the largest bauxite producing state in India.

16. Non-Metallic Minerals do not contain metals or do not have metallic properties. For example, mica, limestone, salt, potash, sulphur, granite, marble, sandstone, etc.

17. Mica can be clear, black, green, red, yellow or brown. Due to its excellent di-electric strength, low power loss factor, insulating properties and resistance to high voltage, it is one of the most essential minerals used in electric and electronic industries. Koderma-Gaya— Hazaribagh belt of Jharkhand is the leading producer of Mica. In Rajasthan, the major mica producing area is around Ajmer. Nellore mica belt of Andhra Pradesh is also an important producer in the country.

18. Limestone (rock mineral) is the basic raw material for the cement industry and essential for smelting iron ore in the blast furnace. It is found in sedimentary rocks of most geological formations. Major limestone-producing states are Andhra Pradesh, Madhya Pradesh, Rajasthan, Gujarat and Tamil Nadu.

19. Minerals are important for every country for its development. Industry and agriculture depend upon minerals and the substances manufactured from them. They are already in short supply. (Just one per cent of the earth’s crust).

20. We are rapidly consuming mineral resources that require millions of years to be created and concentrated. Mineral resources are finite and non-renewable and therefore they must be conserved. Recycling of metals, using scrap metals and other substitutes are steps towards mineral conservation.

Flow-Learning

Words that Matter

1. Mineral: A homogenous, naturally occurring substance with a definable internal structure.
2. Ore: An accumulation of any mineral mixed with other elements.
3. Rocks: Combinations of homogenous substances called minerals.
4. Mineral Ore: Metals in their raw state as extracted from the earth.
5. Non-metallic minerals: Minerals that do not contain metals or do not have metallic properties.
6. Rat hole mining: Coal mining done by family members in the form of long narrow tunnel is known as rat hole mining.

NCERT TEXTBOOK QUESTIONS SOLVED

Question 1. Multiple choice questions:

(i) Which one of the following minerals is formed by decomposition of rocks, leaving a residual mass of weathered materials?
(a) Coal
(b) Bauxite
(c) Gold
(d) Zinc

(ii) Koderma in Jharkhand is the leading producer of which one of the following minerals?
(a) Bauxite
(b) Mica
(c) Iron ore
(d) Copper

(iii) Minerals are deposited and accumulated in the strata of which of the following rocks?
(a) Sedimentary rocks
(b) Metamorphic rocks
(c) Igneous rocks
(d) None of the above

(iv) Which one of the following minerals is contained in the Monazite sand?
(a) Oil
(b) Uranium
(c) Thorium
(d) Coal

Question 2. Answer the following questions in about 30 words:
(i) Distinguish between ferrous and non-ferrous minerals
(ii) What is a mineral?
(iii) How are minerals formed in igneous and metamorphic rocks?
(iv) Why do we need to conserve mineral resources?
Ans. (i) Ferrous and non-ferrous minerals

(ii) Mineral is a homogenous, naturally occurring substance with a definable internal structure. They are formed by a combination of elements. They are an essential part of our lives. The hardest mineral is diamond and the softest is talc. Minerals are usually found in “ores”.
(iii) In igneous and metamorphic rocks, minerals may occur in the cracks, crevices, faults or joints. The smaller occurrences are known as veins and the larger are known as lodes. In most cases, they are formed when minerals in liquid/molten and gaseous forms are forced upwards through cavities towards the earth’s surface. They cool and solidify as they rise.
(iv) We need to conserve mineral resources because they are finite and nonrenewable. Rich mineral deposits are our country’s most valuable but short-lived possessions. Continued extraction of ores leads to increasing costs as mineral extraction comes from greater depths along with decrease in quality.

Activity

Fill the name of the correct mineral in the crossword below:
DOWN
1. Found in placer deposit (4)
2. Iron ore mined in Bailadila (8)
3. Indispensable for electrical industry (4)
4. Geological Age of coal found in north east India (8)
5. Formed in veins and lodes (3)
ACROSS
1. A ferrous mineral (9)
2. Raw material for cement industry (9)
3. Finest iron ore with magnetic properties (9)
4. Highest quality hard coal (10)
5. Aluminium is obtained from this ore (7)
6. Khetri mines are famous for this mineral (6)
7. Formed due to evaporation (6)
Ans. DOWN
1. ROCK                  2. HEMATITE
3. COAL                  4. TERTIARY
5. TIN
ACROSS
1. MANGANESE        2. LIMESTONE
3. MAGNETITE         4. ANTHRACITE
5. BAUXITE              6. COPPER
7. GYPSUM

MORE QUESTIONS SOLVED

I. MULTIPLE CHOICE QUESTIONS
Choose the correct answer:

1. Where are minerals usually found?
(a) Rocks
(b) Earth crust
(c) Ores
(d) Earth core

2. When mining is done by family members in the form of a long narrow tunnel it is known as ……
(a) Narrow tunnel mining
(b) Rat hole mining
(c) Snake mining
(d) Killer mining

3. Minerals occur in igneous and metamorphic rocks in ……… .
(a) the veins and the lodes
(b) layers
(c) alluvial deposits
(d) the decomposed surface rocks

4. Ferrous minerals account for about ……… of the total value of the production of metallic minerals.
(a) one-fourth
(b) three-fourths
(c) one-fifth
(d) one-third

5. Which is the basic mineral and the backbone of industrial development?
(a) Coal
(b) Bauxite
(c) Copper
(d) Iron ore

6. Which metal has a very high content of iron up to 70 per cent?
(a) Magnetite ore
(b) Hematite iron
(c) Hematite ore
(d) Iron ore

7. Which is the largest producer of manganese ores in India?
(a) Kudremukh
(b) Bailadila
(c) Odisha
(d) Jharkhand

8. ……… is the basic raw material for the cement industry and essential for smelting iron ore in the blast furnace.
(a) Gypsum
(b) Limestone
(c) Potash salt
(d) Sodium salt

9. Which one of the following is the hardest mineral?
(a) Gold
(b) Diamond
(c) Ruby
(d) Silver

10. Which one of the following is the softest mineral?
(a) Talc
(b) Toothpaste
(c) Salt
(d) Cement

11. Which one is not a ferrous mineral?
(a) Iron ore
(b) Manganese
(c) Copper
(d) Hematite

12. Bellary-Chitradurga-Chikmaglur-Tumkur belt is located in ……… .
(a) Madhya Pradesh
(b) Karnataka
(c) Andhra Pradesh
(d) Tamil Nadu

13. Which one of the following is not a property of copper?
(a) It is malleable.
(b) It is ductile.
(c) It is good conductor.
(d) It is hard.

14 The largest bauxite-producing state in India is ……… .
(a) Orissa
(b) Madhya Pradesh
(c) Maharashtra
(d) Jharkhand

15. The mineral ore from which aluminium is mainly obtained ……… .
(a) copper
(b) bauxite
(c) iron ore
(d) none of the above

16. The Khetri mines in Rajasthan are famous for which of the following minerals?
(a) Bauxite
(b) Aluminium
(c) Mica
(d) Copper

17. Name the finest iron ore.
(a) Hematite
(b) Magnetite
(c) Manazite
(d) Lignite

18. In which state does Nellore mica belt lie?
(a) Tamil Nadu
(b) Andhra Pradesh
(c) Rajasthan
(d) Karnataka

19. Which of the following minerals are obtained from veins and lodes?
(i) Zinc
(ii) Copper
(iii) Coal
(iv) Bauxite
(a) Only (i) and (ii)
(b) Only (ii) and (iii)
(c) Only (iii) and (iv)
(d) All of the above

20. Which of the following is a famous metal?
(a) Manganese
(b) Bauxite
(c) Gold
(d) Mica

II. VERY SHORT ANSWER TYPE QUESTIONS

Question 1. Which rock consists of single mineral only?
Ans. Limestone consists of a single mineral only.

Question Q2. Which state is the largest producer of manganese ores in India? What was its total productions in the state in 2000-01?
Ans. Odisha is the largest producer of manganese ores in India. It accounted for onethird of the country’s total production in 2000-01.

Question 3. How are minerals indispensable part of our lines?
Ans. Almost everything we use, from a tiny pin to a towering building or a big shop, all are made from minerals. Life processes cannot occur without minerals.

Question 4. How do geologists define minerals?
Ans. Geologists define minerals as a homogenous, naturally occurring substance with a definable internal structure.

Question 5. Name one hardest mineral and one softest mineral.
Ans. Hardest mineral – diamond
Softest mineral – tale

Question 6. Why is copper mainly used in electrical cables, electronics and chemical industries?
Ans. Copper is malleable, ductile and a good conductor of electricity. Therefore, it is mainly used in electrical cables, electronics and chemical industries.

Question 7. Define the term ‘Ore’.
Ans. The term ‘Ore’ is used to describe an accumulation of any mineral mixed with other elements.

Question 8. What is an important condition to make the extraction of minerals commercially viable?
Ans. The mineral context of the ore must be in sufficient concentration.

Question 9. What are veins and lodes?
Ans. In igneous and metamorphic rocks minerals may occur in the cracks, crevices, faults or joints. The smaller occurrences are called veins and the larger are cabled lodes.

Question 10. Name the major metallic minerals which are obtained from veins and lodes.
Ans. Tin, copper, zinc and lead.

Question 11. Where do minerals occur in sedimentary rocks?
Ans. In sedimentary rocks minerals occur in beds or layers.

Question 12. Which minerals are largely derived from ocean waters?
Ans. Common salt, magnesium and bromine are some minerals largely derived from ocean waters.

Question 13. How are ferrous minerals important?
Ans. They are important because they provide a strong base for the development of metallurgical industries.

Question 14. Mention the context of iron present in magnetite.
Ans. A very high context of iron, upto 70 percent, is present in magnetite.

Question 15. What are placer deposits?
Ans. There are some minerals which occur as alluvial deposits in sands of valley floors and the base of hills. These deposits are called placer deposits.

Question 16. Name any four minerals which obtained form placer deposits.
Ans. Gold, silver, tin and platinum.

Question 17. Where are the Kudermukh mines located?
Ans. They are located in the western Ghats of Karnataka.

Question 18. Where is high grade hematite ore found in Orissa?
Ans. In Orissa high grade hematite ore is found in badampahar mines in the Mayurbhanj and Kendujhar districts.

Question 19. What is the main use of manganese?
Ans. Manganese is mainly used in the manufacturing of steel and ferro-manganese alloy.

Question 20. What are ferrous minerals? Give two examples.
Ans. The minerals which contain iron ore are called ferrous minerals. Two examples — manganese, nickel.

Question 21. What are non-ferrous minerals? Give two examples.
Ans. The minerals which do not contain iron ore are called non-ferrous minerals.

Question 22. What are the Khetri mines in Rajasthan famous for?
Ans. The Khetri mines in Rajasthan are famous for copper production.

Question 23. How are bauxite deposits formed?
Ans. Bauxite deposits are formed by decomposition of a wide variety of rocks rich in aluminium silicates.

Question 24. How is aluminium an important metal?
Ans. Aluminium combines the strength of metals such as iron, with extreme lightness and also with good conductivity and great malleability.

Question 25. Name the regions where India’s bauxite deposits are mainly found.
Ans. The Amarkantak plateau, Maikal hills and the plateau region of Bilaspur-Katur.

Question 26. Name the regions where India’s mica deposits are mainly found.
Ans. The northern edge of the Chhota Nagpur plateau.

Question 27. What are a constant threat to miners?
Ans. The risk of collapsing mine roofs, inundation and fires in coalmines are a constant threat to miners.

Question 28. ‘Different regions of India contain different minerals’. What is the reason behind it?
Ans. It happens because of the difference in the geological structure, processes and time involved.

Question 29. Name the two countries which import iron ore from India.
Ans. Japan and South Korea.

III. SHORT ANSWER TYPE QUESTIONS

Question 1. What are non-metallic minerals? Write a short note on uses of mica and its distribution in India.
Ans. Minerals which do not contain metals or do not have metallic properties are called non-metallic minerals. For example, mica, limestone, salt, potash, sulphur, granite, marble, sandstone, etc.
Uses of Mica: Mica is considered to be the most important mineral in electric and electronic industries. Due to its excellent di-electric strength, low power loss factor, insulating properties and resistance to high voltage, it is one of the most essential minerals used in electric and electronic industries.
Distribution of Mica in India: Koderma Gaya–Hazaribagh belt of Jharkhand is the leading producer of Mica. Mica deposits are found in the northern edge of the Chhota Nagpur plateau. In Rajasthan, the major mica producing area is around Ajmer. Nellore mica belt of Andhra Pradesh is also an important producer in the country.

Question 2. Describe any two facts regarding the importance of manganese in our daily life. Also name the four states which are known for its production.
Ans. Manganese is mainly used in the manufacturing of steel and ferro-manganese alloy. Nearly 10 kg of manganese is required to manufacture one tonne of steel. It is also used in manufacturing bleaching powder, insecticides and paints. Orissa is the largest producer of manganese ores in India. It accounted for onethird of the country’s total production in 2000-01. Other manganese-producing states are Madhya Pradesh and Karnataka.

Question 3. State two main uses of copper. Also, mention three major copper-producing districts of India.
Ans. Being malleable, ductile and a good conductor, copper is mainly used in electrical cables, electronics and chemical industries. India is critically deficient in the reserve and production of copper.
Three major copper producing regions of India:
(i) Madhya Pradesh is the largest producer of copper in India. The Balaghat mines in Madhya Pradesh produces 52 per cent of India’s copper.
(ii) Rajasthan is the second largest producer of copper. The Khetri mines in Rajasthan are famous.
(iii) The Singhbhum district of Jharkhand has also large reserves of copper.

Question 4. How is the mining activity injurious to the health of the miners and environment? Explain. 
                              Or
How does mining adversely affect the health and the environment?
Ans. Mining activity is often called a “killer industry” due to high risks involved. The dust and poisonous fumes inhaled by the miners expose them to pulmonary diseases.The risk of collapsing mine roofs, inundation and fires in coalmines are a constant threat to miners. The water sources in the region get contaminated due to mining. Dumping of waste and slurry leads to degradation of land, soil and river pollution.

Question 5. State uses of limestone. Also mention the states where it is produced.
Ans. Limestone is the basic raw material for the cement industry and essential for smelting iron ore in the blast furnace.
It is found in association with rocks composed of calcium carbonates or calcium and magnesium carbonates. It is found in sedimentary rocks of most geological formations.
It is produced in states like Andhra Pradesh, Madhya Pradesh, Rajasthan, Gujarat and Tamil Nadu.

Question 6. The pie chart given below shows the production of manganese in different states. On the basis of reading of diagram answer the following questions:

1. Mention any two uses of Manganese.
2. Which is the largest producer of Manganese?
Ans. 1. Uses of Manganese:
(i) Manganese is mainly used in the manufacturing of steel and ferromanganese alloy. Nearly 10 kg of manganese is required to manufacture one tonne of steel.
(ii) It is also used in manufacturing bleaching powder, insecticides and paints.
2. Odisha is the largest producer of manganese ores in India approximately onethird of the country’s total production.

Question 7. Mention any three major iron-ore belts of India. Write any three characteristics of the southernmost iron-ore belt.
Ans. Three major iron-ore belts of India are:
(i) Odisha – Jharkhand belt
(ii) Durg – bastar – Chandrapur belt in Chhattisgarh and Maharashtra.
(iii) Bellary – Chitradurga – Chikmaglur – Tumkur belt in Karnataka.
Three characteristics of the southernmost iron-ore belt:
(i) The ore is transported as slurry through a pipeline to a port near Mangalore.
(ii) The ores are not of very high quality, yet they are efficiently exploited.
(iii) Iron-ore is exported through Marmagao port.

Question 8. Differentiate between metallic and non metallic minerals with examples.
Ans.

Question 9. Explain any three values attached with the use of minerals in a sustainable manner.
Ans. (i) Our industries and agriculture immensely depend on mineral deposits and the substances manufactured from them. The total volume of workable mineral deposits is an insignificant fraction i.e. one per cent of the earth’s crust. Hence, minerals should be used cautiously.
(ii) The geological processes of mineral formation are so slow that the rates of replenishment are infinitely small in comparison to the present rates of consumption.
(iii) Mineral resources are finite and non-renewable. Rich mineral deposits are our country’s extremely valuable but short-lived possessions.

Question 10. What are the different varieties of iron one? How will you differentiate between them? Give any two points.
Ans. Iron-ore is the backbone of India’s industrial development. The different varieties of iron-ore are-Magnetite, hematite, Limonite and Siderite.
• Magnetite is the finest iron-ore with a very high content of iron up to 70%. It has excellent magnetic qualities. it is valuable for electrical industry.
• Hematite is the most important industrial iron-ore in term of quantity used.
It has a slightly lower iron content than 50-60%.
• Limonite has 40-60% iron content.
• Siderite has 40-50% iron content.

Question 11. How do minerals occur in sedimentary rocks?
Ans. (i) In sedimentary rocks a number of minerals occur in beds or layers.
(ii) They have been formed as a result of deposition, accumulation and concentration in horizontal strata.
(iii) Coal and some forms of iron ore have been concentrated as a result of long periods under great heat and pressure.
(iv) Another group of sedentary numerals such as gypsum, potash salt and sodium salt are formed as a result of evaporation.

Question 12. (i) How are deposits of bauxite formed and aluminium obtained?
(ii) What is the utility of aluminium?
(iii) Describe the distribution of aluminium.
Ans. (i) Bauxite deposits are formed due to decomposition of wide variety of rocks rich in aluminium silicates. Ores containing aluminium are obtained from bauxite which is a clay-like substance from which alumina and later aluminium is obtained.
(ii) It is an important metal because it combines the strength of metals such as iron with good conductivity and great malleability.
(iii) Odisha is the largest bauxite producing state. 45% of country’s total production in 2000-2001 was from Orissa. Panchpatmali deposits in Koraput district are the most important bauxite deposits in the state.

Question 13. How are minerals an indispensable part of our lives? Explain with three examples.
Ans. Minerals from an indispensable part of our lives in the following ways:
(i) From a tiny pin that we use to a towering building or tall ships are all made up of minerals.
(ii) The food that we consume also contains minerals which are essential for the growth of human body.
(iii) Cars, buses, trains and aeroplanes are manufactured with the help of minerals and they run on power resource derived from minerals.

Question 14. State any two factors affecting the economic viability of mineral reserves.
Ans. (i) The mineral content of the ore must be in sufficient concentration to make its extraction commercially viable.
(ii) The type of formation or structure in which minerals are found determines the relative ease with which mineral ores may be mined. This also determines the cost of extraction.

Question 15. (i) How are bauxite formed?
(ii) Where are India’s bauxite deposits found?
(iii) Which are the most important bauxite deposits located in Orissa?
Ans. (i) Bauxite deposits are formed by the decomposition of a wide variety of rocks rich in aluminium silicates.
(ii) India’s bauxite deposits are found in the Amarkantak plateau, Maikal hills and the plateau region of Bilaspur – Katre.
(iii) Panchapatmali deposits in Koraput district the most important bauxite deposits in Orissa.

Question 16. How do minerals occur in igneous and metamorphic rocks?
Ans. In igneous and metamorphic rocks, minerals may occur in the cracks, crevices, faults or joints. The smaller occurrences are known as veins and the larger are known as lodes. In most cases, they are formed when minerals in liquid/molten and gaseous forms are forced upwards through cavities towards the earth’s surface. They cool and solidify as they rise.

Question 17. Explain Rat-Hole mining in the tribal areas.
Ans. (i) In most of the tribal areas of north-east India, minerals are owned by individuals or communities.
(ii) In Meghalaya, there are large deposits of coal, iron-ore, limestone, dolomite etc.
(iii) Coal mining in Jowai and Cherapunjee is done by family members in the form of a long narrow tunnel known as ‘Rat-Hole Mining’.

Question 18. Mention three properties of mica.
Ans. (i) Mica is a mineral made up of a series of plates or leaves.
(ii) It splits easily into thin sheets. These sheets can be so thin that a thousand can be layered into a mica sheet of a few centimeters high.
(iii) Mica can be clear, black, green, red-yellow or brown.
(iv) Due to its excellent di-electric strength, low power loss factor, insulating properties and resistance to high voltage, mica is considered an important mineral used in electric and electronic industries.

III. LONG ANSWER TYPE QUESTIONS

Question 1. Why is conservation of mineral resources essential? Explain any three methods to conserve them.
Ans. The total volume of workable mineral deposits is an insignificant fraction i.e. one per cent of the earth’s crust. We are rapidly consuming mineral resources that took millions of years to be created and concentrated. The geological processes of mineral formation are so slow that the rates of replenishment are infinitely small in comparison to the present rates of consumption. Mineral resources are, therefore, finite and non-renewable. Hence their conservation is essential.
Three methods to conserve minerals:
(i) Mineral resources should be used in planned and sustainable manner.
(ii) Improved technology need to be constantly evolved to allow use of low grade ores at low costs.
(iii) Recycling of metals, using scraps metals and other substitutes are steps in conserving our mineral resources for the future.

Question 2. What are the two main qualities of iron ore deposits of India? Explain the two types of iron ore mainly found in the country. Which are the major states known for the production of iron ore?
Ans. Two qualities of iron ore:
1. Iron ore is the basic mineral and the backbone of industrial development.
2. It provides a strong base for the development of metallurgical industries.
They are of two types: Magnetite and Hematite.
1. Magnetite: It is the finest iron ore. It has a very high content of iron up to 70 per cent. It has excellent magnetic qualities, especially valuable in the electrical industry.
2. Hematite: This ore is the most important industrial iron ore. It is the largest used iron ore in terms of the quantity in India. It has slightly lower iron content than magnetite. (50-60 per cent).
The major iron-ore producing states are Karnataka, Orissa, Chhattisgarh, Goa and Jharkhand.

Question 3. In which various forms do minerals occur?
Ans. Minerals occur in following forms:
1. In igneous and metamorphic rocks, minerals occur in the veins and the lodes. For instance, tin, copper, zinc and lead etc. are obtained from these veins and lodes.
2. In sedimentary rocks minerals occur in beds or layers. They have been formed as a result of deposition, accumulation and concentration in horizontal strata. Coal and some forms of iron ore are found in it. Other groups of Sedimentary minerals such as gypsum, potash salt and sodium salt are formed with the help of evaporation especially in dry regions.
3. Another mode of formation involves the decomposition of surface rocks, and the removal of soluble constituents, leaving a residual mass of weathered material containing ores. Bauxite is formed in this way.
4. Some minerals occur as alluvial deposits in sands of valley floors and base of hills. These deposits contain minerals which are not eroded by water. For example, gold, silver, tin and platinum.
5. Ocean waters contain vast quantities of minerals. Common salts, magnesium and bromine are derived from ocean waters. The ocean beds, too, are rich in manganese nodules.

Question 4. Give an account of the distribution of minerals in India.
                          Or
‘Minerals in India are unevenly distributed’. Explain.
Ans. India is fortunate to have fairly rich and varied mineral resources.
(i) In peninsular plateau the reserves of coal, metallic minerals, mica and many other non-metallic minerals are found.
(ii) In the sedimentary rocks of Gujarat and Assam most of the petroleum deposits are found.
(iii) Rajasthan with the rock systems of the peninsula, has reserves of many nonferrous minerals.
(iv) The alluvial plains of north India are almost devoid of economic minerals.
(v) These variations in the distribution of minerals exist due to differences in the geological structure, process and the time involved in the formation of minerals.

Question 5. Why is Chhotanagpur plateau called a ‘store house of minerals’?
Ans. (i) Chhotanagpur plateau is called a store house of minerals as it has very high grade haematite iron ore.
(ii) The ranges of hills in Chhotanagpur have 14 deposits of super high grade haematite iron ore.
(iii) Most of the mica deposits are found on the northern edge of Chhotanagpur plateau.
(iv) Koderma–Hazaribagh belt of Jharkhand is the leading producer of Mica.

Question 6. Give an account of the major iron ore belts in India.
Ans. The major iron ore belts in India are:
(i) Odisha-Jharkhand belt: In Odisha high grade haematite ore is found in Badampahar mines in the Mayurbhanj and Kendujhar districts. In the adjoining Singbhum district of Jharkhand haematite iron ore is mined in Gua and Noamundi.
(ii) Durg-Bastar-Chandrapur belt lies in Chhattisgarh and Maharashtra. Very high grade haematites are found in the famous Bailadila range of hills in the Bastar district of Chattisgarh. The range of hills comprise of 14 deposits of super high grade haematite from ore. It has the best physical properties needed for steel making. Iron ore from these mines is exported to Japan and South Korea via Vishakapatnam port.
(iii) Bellary-Chitradurga-Chikmaglur-Turnkur belt in Karnataka has large reserves of iron ore. The Kudermukh mines located in the Western Ghatas of Karnataka are a 100 per cent export unit. Kudremukh deposits are known to be one of the largest in the world. The ore is transported as slurry through a pipeline to a port near Mangalore.
(iv) Maharashtra-Goa belt includes the state of Goa and Ratnagiri district of Maharashtra. Though, the ores are not of very high quality, yet they are efficiently exploited iron ore is exported through Mormugao port.

IV. MAP SKILLS

Question 1. On the given political outline map of India, two features A and B are marked. Identify these features with the help of the following information:
A. Iron-ore mines
B. Terminal station of North-South Corridor
On the same map locate and lable the following:
(i) Gandhinagar Software Technology Park.
Ans.

Question 2. Identify the following places marked in the given outline political map of India with the help of references:

Ans. (i) Mayurbhanj                            (ii) Durg
(iii) Bellary                                         (iv) Bailadila
(v) Ajmer                                           (vi) Beawar
(vii) Gaya.

Question 3. Locate and label the following features with appropriate symbols on a political outline map of India.
(i) Balaghat — Manganese                       (ii) Kendujhar — Manganese
(iii) Koraput — Bauxite                            (iv) Bilaspur — Bauxite
(v) Hazaribagh — Mica
Ans.

V. VALUE BASED QUESTIONS

Question 1. Why is conservation of minerals important?
Ans. (i) Minerals are important for the development of a country. Various substances manufactured from minerals industry and agriculture depend on them.
(ii) Minerals are already in short supply and their consumption is so fast. We must keep it in mind that the total volume of workable mineral deposits is an insignificant fraction, i.e. one per cent of the earth’s crust.
(iii) Minerals require millions of years to be created and concentrated. The geological processes of mineral formation are so slow that the rates of replenishment are infinitely small in comparison to present rates of consumption.
(iv) Mineral resources are finite and non-renewable continued extraction of ores leads to increasing costs as mineral extraction comes from greater depths along with the decrease in quality.
It has therefore, become essential to conserve minerals.

Question 2. Suggest some ways to conserve minerals.
Ans. Conservation of minerals is essential ways to conserve them are given below:
(i) All natural resources including minerals should be used judiciously so that future generations may also avail their benefits.
(ii) Recycling of metals should be done.
(iii) Scrap metals and other substitutes should be used.
(iv) Minerals resources should be used in a planned and sustainable manner.
(v) Wastage of minerals should be stopped.

Question 3. How are health and environment affected by the process of mining?
Ans. (i) Mining activity is often called a “killer industry” due to high risks involved.
(ii) The dust and poisonous fumes inhaled by the miners expose them to pulmonary diseases.
(iii) The risk of collapsing mine roofs, inundation and fires in coal mines are a constant threat to miners.
(iv) The water sources in the region get contaminated due to mining.
(v) Dumping of waste and slurry leads to degradation of land, soil and river pollution.

Question 4. Iron ore is the basic mineral of India. How? Which values are associated with it?
Ans. (i) Iron ore is considered the backbone of India’s industrial development.
(ii) They provide a strong base for the development of metallurgical industries in India.

Power Resources

Facts that Matter

1. Energy is required for all activities such as cooking, propelling vehicles, driving machinery in industries, etc. Energy can be generated from fuel minerals like coal, petroleum, natural gas, uranium and electricity. Energy resources can be classified as conventional (firewood, cattle dung cake, coal, petroleum, etc.) and non-conventional sources (solar, wind, biogas, etc.).

2. Coal is an important fossil fuel of India. It provides about 80% of the nation’s energy needs. India is highly dependent on coal for meeting its commercial energy requirements. Coal is found abundantly in the eastern side of the country.

3. In India, coal occurs in rock series of two main geological ages—Gondwana and tertiary. While Gondwana coal is about 200 million years old, tertiary deposits are approximately 55 million years old. The major resources of Gondwana (metallurgical) coal are located in the Damodar valley (West Bengal, Jharkhand), Jharia, Raniganj and Bokaro. The Godavari, Mahanadi, Sone and Wardha valleys also contain coal deposits. Tertiary coals occur in the north-eastern states of Meghalaya, Assam, Arunachal Pradesh and Nagaland.

4. Natural gas is used as a source of energy as well as an industrial raw material in the petrochemical industry. It is considered an environment friendly fuel because of low carbon dioxide emissions. Natural gas is found in Mumbai High and the Gulf of Cambay. Large reserves of natural gas have been discovered in the Krishna- Godavari basin.

5. Petroleum provides fuel for heat and lighting, lubricants for machinery and raw materials for a number of manufacturing industries. Petroleum refineries act as a “nodal industry” for synthetic textile, fertiliser and numerous chemical industries. About 63 per cent of India’s petroleum production is from Mumbai High, 18 per cent comes from Gujarat and 16 per cent from Assam.

6. Electricity is generated mainly in two ways by hydro turbines to generate hydro electricity and by burning other fuels such as coal, petroleum and natural gas to produce thermal power. Hydro electricity is a renewable resource.

7. Non-conventional sources of energy such as solar energy, wind, etc. are renewable and therefore there is a pressing need to use these sources.

8. Nuclear or Atomic energy is obtained by altering the structure of atoms. Uranium and thorium, which are available in Jharkhand and the Aravalli ranges of Rajasthan are used for generating atomic or nuclear power. The Monazite sand of Kerala is also rich in thorium.

9. Being a tropical country, India has an abundance of sunlight. Hence, there are huge possibilities of tapping solar energy. Use of solar energy will be able to minimise the dependence of rural households on firewood and dung cakes, which in turn will contribute to environmental conservation and adequate supply of manure in agriculture. Photovoltaic technology converts sunlight directly into electricity. The largest solar plant of India is located at Madhapur, near Bhuj (Gujarat).

10. Wind power is abundant in India. The largest wind farm cluster is located in Tamil Nadu from Nagarcoil to Madurai. Other states with wind farms are Andhra Pradesh, Karnataka, Gujarat, Kerala, etc. Nagarcoil and Jaisalmer make effective use of wind energy.

11. Biogas is produced from shrubs, farm waste, animal and human wastes. It is mostly used for domestic consumption in rural areas. Biogas plants using cattle dung are known as ‘Gobar gas plants’ in rural India.

12. These provide twin benefits to the farmer in the form of energy and improved quality of manure. Biogas is by far the most efficient use of cattle dung. It prevents the loss of trees and manure due to burning of fuel wood and cow dung cakes.

13. Oceanic tides can be used to generate electricity which is known as tidal energy.

14. Floodgate dams are built across inlets. During high tide water flows in to the inlet and gets trapped when the gate is closed. After the tide falls outside the flood gate, the water retained by the floodgate flows back to the sea via a pipe that carries it through a power-generating turbine. In India, the Gulf of Kuchchh provides ideal conditions for utilising tidal energy.

15. Geothermal energy refers to the heat and electricity produced by using the heat from the interior of the earth. Two experimental projects have been set up in India to harness geothermal energy. One is located in the Parvati valley near Manikarn in Himachal Pradesh and the other is located in the Puga Valley, Ladakh.

16. Energy is a basic requirement for economic development. Every sector of national economy— agriculture, industry, transport, commercial and domestic—needs inputs of energy. There is an urgent need to develop a sustainable path of energy development. India is presently one of the least energy efficient countries in the world. We have to adopt a cautious approach for judicious use of our limited energy resources.

Words that Matter

1. Lignite: It is a low grade brown coal, which is soft with high moisture content.
2. Bituminous: Coal that has been buried deep and subjected to increased temperatures is bituminous coal.
3. Anthracite: It is the highest quality of hard coal.
4. Hydro-electricity: It is generated by fast flowing water.
5. Thermal electricity: It is generated by using coal, petroleum and natural gas.
6. Tidal energy: It refers to the electricity which is generated by oceanic tides.
7. Geo-thermal energy: It refers to the heat and electricity produced by using the heat from the interior of the Earth.
8. Biogas: It is produced by using shrubs, farm waste, animal and human waste.

NCERT TEXTBOOK QUESTIONS SOLVED

Question 1. Answer the following questions in about 30 words:
Distinguish between conventional and non-conventional sources of energy.
Ans. Conventional and non-conventional sources of energy

Question 2. Answer the following questions in about 120 words.
(i) Describe the distribution of coal in India.
(ii) Why do you think that solar energy has a bright future in India?
Ans. (i) Coal is an important fossil fuel of India. It is the most abundantly available fossil fuel. It provides about 80% of the nation’s energy needs. India is highly dependent on coal for meeting its commercial energy requirements. In India, coal occurs in rock series of two main geological ages—Gondwana and tertiary. While Gondwana coal is about 200 million years old, tertiary deposits are approximately 55 million years old. The major resources of Gondwana coal which are metallurgical coal, are located in the Damodar valley (West Bengal, Jharkhand). Jharia, Raniganj and Bokaro are important coalfields. The Godavari, Mahandi, Sone and Wardha valleys also contain coal deposits. Tertiary coals occur in the north-eastern states of Meghalaya, Assam, Arunachal Pradesh and Nagaland.
(ii) (a) Being a tropical country, India has an abundance of sunlight. Hence, there are huge possibilities of tapping solar energy.
(b) Photovoltaic technology converts sunlight directly into electricity. Solar energy is becoming popular in rural and remote areas.
(c) Use of solar energy will be able to minimise the dependence of rural households on firewood and dung cakes, which in turn will contribute to environmental conservation and adequate supply of manure in agriculture.
(d) Solar energy is a non-conventional source of energy and also ecofriendly. The largest solar plant of India is located at Madhapur, near Bhuj (Gujarat) where solar energy is used to sterlise milk cans.

MORE QUESTIONS SOLVED

I. MULTIPLE CHOICE QUESTIONS
Choose the correct answer:

1. Which one is not a conventional source of energy?
(a) Coal
(b) Biogas
(c) Firewood
(d) Petroleum

2. Decaying plants in swamps produce what ……… .
(a) Peat
(b) Lignite
(c) Bituminous
(d) Coal

3. The principal lignite reserves are used for ……… .
(a) Generation of wind power
(b) Generation of electricity
(c) Generation of thermal power
(d) None of the above

4. The major resources of Gondwana coal are located in ……… .
(a) Wardha valley
(b) Godavari valley
(c) Sone valley
(d) Damodar valley

5. Heavy industries and thermal power stations are located on or near the coalfields because ……… .
(a) coal is a bulky material
(b) coal loses weight on use
(c) coal transportation is very costly
(d) all of the above

6. The oldest oil-producing state in India is ……… .
(a) Assam
(b) Gujarat
(c) Maharashtra
(d) Tamil Nadu

7. The full form of CNG is ……… .
(a) Compound Natural Gas
(b) Complex Natural Gas
(c) Compound New Gas
(d) Compressed Natural Gas

8. There are over ……… thermal power plants in India.
(a) 210
(b) 310
(c) 410
(d) 510

9. The largest solar plant of India is located at ……… .
(a) Madhapur
(b) Nagarcoil
(c) Jaisalmer
(d) Madurai

10. Nagarcoil and Jaisalmer are well known for effective use of ……… in the country.
(a) solar energy
(b) wind energy
(c) tidal energy
(d) atomic energy

11. The most important oil field in Gujarat is ……… .
(a) Ankaleshwar
(b) Vadodara
(c) Kalol
(d) Hajira

12. Neyveli has reserves of ……… .
(a) Anthracite
(b) Poat
(c) Lignite
(d) Bituminous

13. Which one of the following non-conventional sources of energy is harnessed in the Parvati Valley near Manikaran in Himachal Pradesh?
(a) Solar energy
(b) Tidal energy
(c) Geothermal energy
(d) Wind energy

14. Which one of the following fuels is considered environment-friendly?
(a) Coal
(b) Petroleum
(c) Natural gas
(d) Firewood

15. About sixty per cent of India’s petroleum production comes from the region of ……….
(a) Gujarat
(b) Rajasthan
(c) Assam
(d) Mumbai High

16. Tertiary coal occur in the region of ……… .
(a) Damodar valley
(b) Wardha valley
(c) Godavari valley
(d) North-eastern states

II. VERY SHORT ANSWER TYPE QUESTIONS

Question 1. Mention any four activities which require energy.
Ans. Energy is needed to
(i) Cook food
(ii) Provide light and heat
(iii) Propel vehicles
(iv) Drive machinery in industries

Question 2. Mention any four conventional sources of energy.
Ans. Firewood, cattle dung cake, coal and natural gas are conventional sources of energy.

Question 3. Mention any four unconventional sources of energy.
Ans. Solar, wind, tidal and bio-gas are the unconventional sources of energy.

Question 4. Which are the two most common sources of energy in rural India?
Ans. Firewood and cattle dung cake are the two most common sources of energy in rural India.

Question 5. Why is using dung cake being discouraged?
Ans. Using dung cake is being discouraged because it consumes most valuable manure which could be used in agriculture.

Question 6. Which is the most abundantly available fossil fuel?
Ans. Coal is the most abundantly available fossil fuel.

Question 7. How is coal formed?
Ans. Coal is formed due to the compression of plant material over millions of years.

Question 8. How is peat produced? Mention one feature of it.
Ans. Peat is produced by decaying of plants in swamps.
Features: It has a low carbon high moisture contents and low heating capacity.

Question 9. Which is a low grade brown coal? Mention one feature of it?
Ans. Lignite is a low grade brown coal.
Feature: It is soft with high moisture content.

Question 10. Where are the principal lignite reserves found?
Ans. The principal lignite reserves are found in Neyveli in Tamil Nadu.

Question 11. Which is the most popular coal?
Ans. Biluminous coal is the most popular coal.

Question 12. Which is the highest quality hard coal?
Ans. Anthracite is the highest quality hard coal.

Question 13. Name two important coalfields of India.
Ans. Jharia and Bokaro.

Question 14. How is natural gas used?
Ans. Natural gas is used as a source of energy as well as an industrial raw material in the petrochemical industry.

Question 15. Why is natural gas considered an environment-friendly fuel?
Ans. Natural gas is considered an environment-friendly fuel because of low carbon dioxide emissions.

Question 16. Name the key users of natural gas.
Ans. The power and fertiliser industries are the key users of natural gas.

Question 17. How is hydro-electricity generated?
Ans. Hydro-electricity is generated by fast flowing water.

Question 18. Name a few multi-purpose projects of India.
Ans. (i) Bhakra Nangal
(ii) Damodar Valley Corporation
(iii) Kopili Tydel Project

Question 19. How is thermal electricity generated?
Ans. Thermal electricity is generated by using coal, petroleum and natural gas.

Question 20. How many thermal power plants are there in India?
Ans. There are over 310 thermal power plants in India.

Question 21. Where are uranium and thorium available in India? What are they used for?
Ans. Uranium and thorium are available in Jharkhand and the Aravali ranges of Rajasthan. They are used for generating atomic or nuclear power.

Question 22. Where is the largest wind farm cluster located in India?
Ans. The largest wind farm cluster is located in Tamil Nadu from Nagarcoil to Madurai.

Question 23. Which energy can be produced from ocean water?
Ans. Tidal energy can be produced from ocean water.

Question 24. Which region of India provides ideal conditions for utilising tidal energy?
Ans. In India, the Gulf of Kuchchh provides ideal conditions for utilising tidal energy.

Question 25. What is meant by geo-thermal energy?
Ans. Geothermal energy refers to the heat and electricity produced by using the heat from the interior of the earth.

II. SHORT ANSWER TYPE QUESTIONS

Question 1. In the present day energy crisis what steps will you like to take for saving energy?
Ans. (i) Energy is a basic requirement for economic development. Hence, there is an urgent need to develop a sustainable path of energy development. Promotion of energy conservation and increased use of renewable energy sources are the twin planks of sustainable energy.
(ii) We have to adopt a cautious approach for the judicious use of our limited energy resources. As concerned citizens we can do our bit by using public transport systems instead of individual vehicles.
(iii) Switching off electricity when not in use, using power-saving devices and using non-conventional sources of energy are other important steps for saving energy.

Question 2. Why is the use of non-conventional sources of energy becoming essential these days? 
Ans. The use of non-conventional sources of energy is becoming necessary because of the following reasons:
(i) The growing consumption of energy in the country has made us dependent on fossil fuels such as coal, oil and gas and it may lead to shortages in the supply of oil, gas and coal in future.
(ii) Rising prices of oil and gas has adversely affected the foreign exchange.
(iii) The growth of the national economy is getting slowed down.
(iv) Ever-increasing use of fossil fuels is causing serious environmental problems.
(v) Non-conventional sources of energy are renewable and also eco-friendly.

Question 3. What efforts can be made to conserve energy resources in India?
Ans. Following efforts can be made to conserve energy resources in India:
(i) Using public transport instead of individual vehicle.
(ii) Switching off electricity when not in use.
(iii) Using power-saving devices.
(iv) Non-conventional resources should be used more and more because they are renewable and eco-friendly.
(v) Use of automobiles, engines should be decreased and electric motors should be introduced.
(vi) Judicious use of our limited energy resources.

Question 4. Which is the most abundantly available fossil fuel in India? What are the four major forms of it? Write main features of each form.
Ans. Coal is an important and abundantly available fossil fuel in India. It is formed due to the compression of plant material over millions of years. It is a bulky material and loses weight on use as it is reduced to ash.
The four major forms of coal are:
(i) Peat: Decaying plants in swamps produce peat. It has a low carbon and high moisture contents and low heating capacity.
(ii) Lignite is a low grade brown coal, which is soft with high moisture content. The principal lignite reserves are in Neyveli in Tamil Nadu and are used for generation of electricity.
(iii) Bituminous coal is buried deep and subjected to increased temperatures. It is the most popular coal in commercial use. Metallurgical coal is high grade bituminous coal which has a special value for smelting iron in blast furnaces.
(iv) Anthracite is the highest quality hard coal.

Question 5. “India is highly dependent on coal for meeting its commercial energy requirement.” Support the statement with three arguments.
Ans. (i) In India, coal is the most abundantly available fossil fuel. It provides a substantial part of the nation’s energy needs.
(ii) It is used for power generation, to supply energy to industry as well as for domestic needs.
(iii) It is used as a raw material in the making of coal tar and coal gas.

Question 6. How is biogas produced? Why it is called ‘Gobar gas plant’ in rural area?
Ans. (i) Biogas is produced from shrubs, farm waste, animal and human wastes. It is mostly used for domestic consumption in rural areas.
(ii) Decomposition of organic matter yields gas, which has higher thermal efficiency in comparison to kerosene, dung cake and charcoal.
(iii) Biogas plants are set up at municipal, cooperative and individual levels. Biogas plants using cattle dung are known as Gobar gas plants in rural India.
(iv) These provide twin benefits to the farmer in the form of energy and improved quality of manure.
(v) Biogas makes the most efficient use of cattle dung.
(vi) It prevents the loss of trees and manure due to burning of fuel wood and cow dung cakes.

Question 7. Which is the next major source of energy after coal, in India? Describe any two advantages of it.
Ans. Petroleum is a major energy source in India after coal. The two advantages of petroleum are:
(i) It provides fuel for heat and lighting, lubricants for machinery and raw materials for a number of manufacturing industries.
(ii) Petroleum refineries act as a “nodal industry” for synthetic textile, fertiliser and numerous chemical industries.
(iii) About 63 per cent of India’s petroleum production is from Mumbai High, 18 per cent comes from Gujarat and 16 per cent from Assam.

Question 8. How is Nuclear energy obtained?
Ans. Nuclear energy is obtained by altering the structure of atoms. When such an alteration is made, much energy is released in the form of heat and this is used to generate electric power. Uranium and Thorium, which are available in Jharkhand and the Aravalli ranges of Rajasthan are used for generating atomic or nuclear power. The monazite sands of Kerala is also rich in Thorium.

Question 9. What are the various uses of coal?
Ans. Coal provides a substantial part of the nation’s energy needs. It is used:
(i) for power generation
(ii) to supply energy to industry as well as for domestic needs. India is highly dependent on coal for meeting its commercial energy requirements.

Question 10. Why is solar energy more developed in western Rajasthan? Give three points to support your answer.
Ans. (i) Western Rajasthan is blessed with an abundance of sunlight.
(ii) It has less tree cover.
(iii) It has very less rainfall as it is located on the leeward side of the western ghats.

Question 11. Give a brief description of the petroleum occurrences in India.
Ans. The petroleum occurrences in India are usually associated with anticlines and fault trap in rock formations of the tertiary age. In regions of folding, anticlines or domes, it occurs where oil is trapped in the crest of the up fold. The oil bearing layer is a porous limestone or sandstone through which oil may flow. The oil is prevented from rising or sinking by interviewing non-porous layers.
Petroleum is also found in fault traps between porous and non-porous rocks. Gas, being lighter, usually occurs above the oil.

Question 12. Mention three merits of natural gas.
Ans. (i) Natural gas is an important clean energy resource found in association with or without petroleum.
(ii) It is used as a source of energy as well as an industrial raw material in the petrochemical industry.
(iii) It is considered an environment-friendly fuel because of low carbon dioxide emissions.

Question 13. Give an account of the distribution of natural gas in India.
Ans. (i) Large reserves of natural gas are found in Krishna Godavari basin.
(ii) Along the west-coast the reserves of the Mumbai High and allied fields are supplemented by finds in the Gulf of Cambay.
(iii) Andaman and Nicobar islands are also important areas having large reserves of natural gas.

Question 14. Distinguish between natural gas and bio-gas.
Ans. Differences between natural gas and bio-gas are given below:

Question 15. Explain the formation of coal. Also mention the factors which decide the variety of coal.
Ans. Coal is formed due to the compression of plant material over millions of years. Coal is found in a variety of forms depending on the degrees of compression and the depth and time of burial.

Question 16. Why is it necessary to develop the tidal and wind energy solve the present day energy crises? Support your answer with three points.
Ans. (i) Energy is the basic requirement for economic development in every sector of our economy.
(ii) In the domestic sector, the demand of energy is growing due to the increase in the use of electrical gadgets.
(iii) India has a large coastline. Therefore, oceanic tides can be used to generate electricity.

Question 17. What is solar energy? What is its importance?
Ans. The energy obtained from the sun is known as the solar energy. Its importance can be understood by the following points.
(i) Solar energy does not cause environmental problems as it is pollution free.
(ii) India has enormous possibilities of tapping solar energy.
(iii) It is becoming popular in rural and remote areas of India. Thus, it will be able to minimise the dependence of rural households on firewood and dung cake.

III. LONG ANSWER TYPE QUESTIONS

Question 1. Which source of energy is natural gas? Write in brief about it.
Ans. Natural gas is a conventional source of energy. It is an important clean energy resource found in association with or without petroleum. It is used as a source of energy as well as an industrial raw material in the petro-chemical industry.
Natural gas is considered an environment friendly fuel because of low carbon dioxide emissions and is, therefore, the fuel for the present century.
Large reserves of natural gas have been discovered in the Krishna-Godavari basin. Along the west coast the reserves of the Mumbai High and allied fields are supplemented by finds in the Gulf of Cambay. Andaman and Nicobar islands are also important areas having large reserves of natural gas.
The 1700 km long Hazira-Vijaipur-Jagdishpur cross country gas pipeline links Mumbai High and Bassien with the fertiliser, power and industrial complexes in western and northern India. The power and fertiliser industries are the key users of natural gas. Compressed Natural Gas (CNG) is now being used in vehicles.

Question 2. Why do we need to conserve energy resources?
Ans. We need to conserve energy resources because of the following reasons:
(i) Energy is a basic requirement for economic development. Every sector of national economy—agriculture, industry, transport, commercial and domestic—needs inputs of energy.
(ii) There is an urgent need to develop a sustainable path of energy development.
(iii) India is presently one of the least energy efficient countries in the world. We have to adopt a cautious approach for judicious use of our limited energy resources.
(iv) Various development plans require increasing amount of energy to remain operational.
(v) The success of economic development plans depends on energy resources.
(vi) Consumption of energy in all forms has been steadily rising all over the country. Therefore, it is necessary to minimise its consumption. We must keep it in mind that our energy resources are limited.
(vii) There is an urgent need to develop a sustainable path of energy development. We should promote energy conservation and use of renewable energy resources.

Question 3. What is geothermal energy? Write in detail about it.
Ans. Geothermal energy refers to the heat and electricity produced by using the heat from the interiors of the Earth.
Geothermal energy exists because the Earth grows progressively hotter with increasing depth. Where the geothermal gradient is high, high temperatures are found at shallow depths. Ground water in such areas absorbs heat from the rocks and becomes hot. It is so hot that when it rises to the earth’s surface, it turns into steam. This steam is used to drive turbines and generate electricity. There are several hundred hot springs in India which could be used to generate electricity. Two experimental projects have been set up in India to harness geothermal energy. One is located in the Parvati valley near Manikarn in Himachal Pradesh and the other is located in the Puga Valley, Ladakh.

Question 4. What are the four types of coal? Write one main characteristics of each.
Ans. Coal is an important and abundantly available fossil fuel in India. It is formed due to the compression of plant material over millions of years. It is a bulky material and loses weight on use as it is reduced to ash.
The four major forms of coal are:
(i) Peat: Decaying plants in swamps produce peat. It has a low carbon and high moisture contents and low heating capacity.
(ii) Lignite is a low grade brown coal, which is soft with high moisture content. The principal lignite reserves are in Neyveli in Tamil Nadu and are used for generation of electricity.
(iii) Bituminous coal is buried deep and subjected to increased temperatures. It is the most popular coal in commercial use. Metallurgical coal is high grade bituminous coal which has a special value for smelting iron in blast furnaces.
(iv) Anthracite is the highest quality hard coal.

Question 5. Bring out the differences between thermal power and hydel power project.
Ans. The differences between thermal power and hydel power project are given below:

Question 6. Name any four nuclear or atomic power stations in India.
Ans. (i) Rawat Bhata in Rajasthan
(ii) Naraura in Uttar Pradesh
(iii) Kaiga in Karnataka
(iv) Kalpakkam in Tamil Nadu

Question 7. What is tidal energy? Name a region of India which provides ideal conditions for utilising tidal energy.
Ans. Oceanic tides can be used to generate electricity. Floodgate dams are built across inlets. During high tide water flows into the inlet and gets trapped when the gate is closed. After the tide falls outside the flood gate, the water retained by the floodgate flows back to the sea via pipe that carries it through a power generating turbine. In India, the Gulf of Kuchchh, provides ideal conditions for utilising tidal energy. A 900 mw tidal energy power plant is set up here by the National Hydropower Corporation.

Question 8. Explain any five points of significance of bio-gas generation in the rural areas of India.
Ans. (i) Biogas is produced from shrubs, farm waste, animal and human wastes. It is mostly used for domestic consumption in rural areas.
(ii) Decomposition of organic matter yields gas, which has higher thermal efficiency in comparison to kerosene, dung cake and charcoal.
(iii) Biogas plants are set up at municipal, cooperative and individual levels. Biogas plants using cattle dung are known as Gobar gas plants in rural India.
(iv) These provide twin benefits to the farmer in the form of energy and improved quality of manure.
(v) Biogas makes the most efficient use of cattle dung.
(vi) It prevents the loss of trees and manure due to burning of fuel wood and cow dung cakes.

Question 9. What are the uses of petroleum? Suggest any two ways to save petroleum.
Ans. Petroleum, also known as mineral oil, is the next major energy source in India after coal. Its uses are given below:
(i) It provides fuel for heat and lighting.
(ii) It provides lubricants for machinery.
(iii) It provides raw materials for a number of manufacturing industries.
(iv) Petroleum refineries act as a ‘vodal industry’ for synthetic textile, fertiliser and numinous chemical industries.
Two Ways to Save Petroleum
(i) Maximum use of public transport instead of individual vehicles.
(ii) Putting off vehicles at red lights.

IV. MAP SKILLS

Question 1. Identify the following places marked in the given outline political map of India with the help of references.

Ans. (i) Neyveli                 (ii) Singareni
       (iii) Talcher                (iv) Korba
       (v) Digboi                  (vi) Kalol
       (vii) Bassein               (viii) Mumbai High.

Question 2. Locate and label the following on an outline political map of India:
• Thermal power plants—Namrup, Talcher, Korba, Ramagundam, Vijayawada and Tuticorin.
• Nuclear power plants—Narora, Rawat Bhata, Tarapur, Kaiga and Kalpakkam.
Ans.

V. VALUE BASED QUESTIONS

Question 1. How can we save our limited energy sources? Suggest ways for its judicious use.
                           Or
“We have to adopt a cautious approach for the judicious use of our limited energy resources”. Support the statement with three examples.
Ans. Since we have limited energy sources, it is our prime duty to conserve them as far as possible:
Ways to conserve energy sources:
(i) Using public transport instead of individual vehicles.
(ii) Switching off electricity when not in use.
(iii) Using non-conventional sources more and more.
(iv) Using power saving devices.
We should promptly adopt the above measures in order to save energy. We must keep it in mind that energy saved is energy produced.

Question 2. The use of non-conventional sources of energy should be encouraged. What may be the reason behind this?
                           Or
Explain why the use of non-conventional sources of energy is becoming necessary in our country? Give three reasons.
                           Or
What are non-conventional sources of energy? Why is there a pressing need to use these sources of energy?
Ans. The use of non-conventional sources of energy is becoming necessary because:
(i) In the growing consumption of energy in the country has made us dependent on fossil fuels such as coal, oil and gas and it may lead to shortages in the supply of oil, gas and coal in future.
(ii) Rising prices of oil and gas has adversely affected the foreign exchange.
(iii) The growth of the national economy is getting slowed down.
(iv) Ever-increasing use of fossil fuels is causing serious environmental problems.
(v) Non-conventional sources of energy are renewable and also eco-friendly.