CBSE Class 8 Social Science Chapter 3: Mineral and Power Resources NCERT Solutions

(i) Three common minerals that we use in our daily lives are copper, iron, and salt. Copper is used in electrical wiring and utensils, iron is essential for making steel used in construction and machinery, and salt is a vital part of our diet and used in various industries.

(ii) An ore is a type of rock that contains one or more valuable minerals, from which these minerals can be economically extracted. Ores of metallic minerals are typically found in igneous and metamorphic rock formations, often located deep within the Earth's crust or in mountain ranges.

(iii) Two regions in India that are rich in natural gas resources are Jaisalmer in Rajasthan and the Krishna-Godavari delta region in Andhra Pradesh.

(iv) The suggested sources of energy for different areas are:

(a) For rural areas: Solar energy and wind energy are suitable. These areas often have open spaces with fewer obstructions, allowing for efficient capture of sunlight and wind power.

(b) For coastal areas: Wind energy and tidal energy are good choices. Coastal regions benefit from consistent sea breezes for wind turbines and the potential of tidal movements for generating energy.

(c) For arid regions: Wind energy and solar energy are feasible. Similar to rural areas, arid regions usually have ample sunlight and open spaces suitable for solar panels and wind turbines.

(v) Five ways to save energy at home include:

(a) Promoting and utilizing solar energy for heating water or other applications whenever possible.

(b) Using biogas, derived from organic waste, as a cooking fuel, especially in rural settings.

(c) Drying clothes in sunlight instead of using electric dryers, which saves electricity and reduces carbon emissions.

(d) Practicing energy conservation by switching off fans, lights, and other electrical appliances when they are not in use.

(e) Using pressure cookers for cooking food, as they significantly reduce cooking time and thus save fuel or electricity.

(i) The correct answer is (c) They are inexhaustible. Minerals are finite resources and can be depleted; therefore, they are exhaustible, not inexhaustible.

(ii) The correct answer is (b) Karnataka. Jharkhand, Rajasthan, and Andhra Pradesh are significant producers of mica in India. Karnataka is not a major producer compared to the others.

(iii) The correct answer is (c) Chile. Chile is one of the world's largest producers of copper, known for its vast copper reserves and significant global output.

(iv) The correct answer is (d) Cooking food in an open pan kept on low flame. Cooking in an open pan on a low flame is inefficient and consumes more LPG compared to other methods like using a pressure cooker or preparing ingredients beforehand.

(i) Building huge dams can significantly alter the local environment. It leads to the submergence of large areas of land, displacing communities and destroying natural habitats for plants and animals. This can disrupt ecosystems, affect biodiversity, and change river flow patterns downstream. Therefore, a thorough assessment of these environmental impacts is crucial before undertaking such projects.

(ii) Industries, particularly those that are energy-intensive or require raw materials like coal, are often concentrated around coal mines to reduce transportation costs and ensure a steady, readily available supply of fuel. Proximity to coal mines makes it easier and cheaper to procure coal, which is a primary energy source for many industries, thereby improving operational efficiency.

(iii) Petroleum is referred to as "black gold" because it is an extremely valuable and versatile fossil fuel. It is a crucial source of energy for transportation (cars, planes, ships), power generation, and as a raw material for a vast array of products, including plastics, chemicals, and medicines. Its high economic value and widespread use make it comparable to gold.

(iv) Quarrying, the process of extracting stone or minerals from the ground, can become a major environmental concern. When quarries are abandoned, they often leave behind large, deep pits that can be hazardous and unsightly. The process can also lead to soil erosion, dust pollution, noise pollution, and can damage local water sources and ecosystems. Proper land reclamation and management are necessary to mitigate these environmental issues.

(i) Conventional Sources of Energy are those that have been in use for a long time and are generally finite, meaning they are being depleted faster than they can be replenished. Examples include fossil fuels like coal, petroleum, and natural gas, as well as firewood.

Non-conventional Sources of Energy are those that have come into use more recently, are often renewable, and are considered more sustainable. They are being developed to address the depletion of conventional resources and growing environmental concerns. Examples include solar energy, wind energy, tidal energy, geothermal energy, and biogas.

(ii) Biogas is produced from the decomposition of organic waste (like animal dung, plant matter, and sewage) in the absence of oxygen, typically in a biogas digester. It is a renewable energy source and considered non-conventional. It is primarily used as a cooking fuel.

Natural Gas is a fossil fuel found deep within the Earth, often alongside petroleum deposits. It is a non-renewable energy source and considered conventional. It is extracted and purified before being used for heating, electricity generation, and as a fuel for vehicles.

(iii) Ferrous Minerals are minerals that contain iron. They are typically magnetic and form the basis of the iron and steel industry. An example is iron ore itself.

Non-ferrous Minerals are minerals that do not contain iron. They are generally non-magnetic and are used in various industries for their specific properties. Examples include copper, bauxite (for aluminum), and gold.

(iv) Metallic Minerals are minerals that contain one or more metallic elements. They are usually hard, possess luster, and are good conductors of heat and electricity. They can be further classified into ferrous and non-ferrous minerals. Examples include iron ore, copper, and bauxite.

Non-metallic Minerals are minerals that do not contain metals. They are generally not good conductors of heat and electricity and do not possess metallic luster. Examples include limestone, mica, coal, and salt.