Practice Questions: Minerals & Energy Resources

Q1: Why is there a wide range of colours, hardness, crystal forms, lustre and density found in minerals?
Ans: A wide range of colours, hardness, crystal forms, lustre and density is found in minerals because each mineral is made up of a particular combination of chemical elements and their atoms are arranged in specific ways. The physical and chemical conditions during formation - such as temperature, pressure and the presence of other elements - affect how atoms bond and are packed. These differences in composition and internal structure produce variations in colour, hardness, crystal shape, lustre and density among minerals.

Q2: How do minerals occur in igneous and metamorphic rocks?
Ans: In igneous and metamorphic rocks, minerals commonly occur in cracks, crevices, faults or joints where mineral-rich fluids have moved and deposited material. Smaller mineral-filled fractures are called veins, while larger, more extensive mineral concentrations are called lodes. These deposits form when hot fluids cool and minerals crystallise or when pressure and temperature changes concentrate certain elements in fractures.

Q3: How do minerals occur in sedimentary rocks?
Ans: In sedimentary rocks, minerals are often deposited as horizontal beds or layers. They accumulate from sediments carried by water, wind or ice and settle in layers called strata. Over time, these layers are compacted and cemented to form sedimentary rocks with mineral deposits arranged in nearly horizontal sequences.

Q4: Why should the use of cattle cake as fuel be discouraged?
Ans: The use of cattle (cow) dung cakes as fuel should be discouraged because they are a valuable source of organic manure. Burning dung cakes removes nutrients that could enrich soil and improve crop yields, leading to reduced soil fertility over time. In addition, indoor burning of dung cakes produces smoke and harmful particulates that harm human health. Instead, cow dung should be used for producing biogas or as compost, which gives both energy and a useful fertiliser without degrading soil quality.

Q5: How are gobar gas plants beneficial to the farmers?
Ans: Gobar (biogas) plants benefit farmers in several ways:

• They provide a clean and reliable source of fuel for cooking and lighting, reducing dependence on firewood and dung cakes.
• The leftover slurry from the biogas plant is an improved quality manure, rich in nutrients and easier to apply to fields than raw dung.
• They help in managing farm and household waste in an environmentally friendly way and reduce indoor air pollution.

Q6: 'There is a pressing need to use renewable energy resources.' Justify the statement with suitable arguments.
Ans: The statement can be justified by the following arguments.

• Increased consumption of energy has raised dependence on fossil fuels such as coal, oil and natural gas, which are limited in supply.
• There are uncertainties about future supplies because fossil fuels are finite and may become scarce or more expensive.
• Non-renewable sources contribute to pollution and environmental degradation, which harm health and ecosystems.
• Renewable sources such as solar, wind, tidal, biomass and energy from waste are sustainable, cause less pollution and reduce long-term costs when deployed widely.

Q7: Explain the importance of conservation of minerals. Highlight any three measures to conserve them.
Ans: Mineral conservation is essential because:

• Minerals are non-renewable and finite; once used, they cannot be replaced on a human timescale.
• Their formation takes millions of years, so the rate of consumption far exceeds the rate of formation.
• As shallow, high-quality deposits are exhausted, extraction becomes deeper and costlier, and ore quality may decline.

Three methods to conserve minerals are:

• Use minerals in a planned and sustainable manner, prioritising reuse and avoiding wasteful consumption.
• Develop improved technologies to process and make economic use of low-grade ores, reducing the need to mine new high-grade deposits.
• Promote recycling and the use of scrap metals and substitutes to lower demand for newly mined minerals.

Q8: How is the mining activity injurious to the health of the miners and environment? Explain.
Ans: Mining activity affects both the health of miners and the surrounding environment in several ways.

• Health risks to miners: inhalation of dust and poisonous gases can lead to pulmonary diseases (like pneumoconiosis), exposure to toxic substances can cause long-term illnesses, and accidents such as roof collapse, inundation and fires (especially in coal mines) endanger lives.
• Environmental effects: mining contaminates surface and groundwater through acid mine drainage and chemicals; dumping of waste and slurry degrades land and soil; and particulate emissions and effluents cause air and water pollution, harming plants, animals and local communities.

Q9: How can biogas solve the energy problem mainly in rural India? Give your suggestions.
Ans: Biogas can address rural energy needs in several important ways:

• It converts farm and animal waste into a clean fuel for cooking and lighting, reducing dependence on firewood and dung cakes and lowering indoor pollution.
• The spent slurry from biogas plants is an improved organic fertiliser, which enhances soil fertility and crop yields.
• Biogas plants promote waste management and generate energy locally, making them especially suitable for decentralised rural communities.

Suggestions to expand use of biogas:

• Provide subsidies and technical support to install and maintain family and community biogas units.
• Train local technicians for operation and repair to ensure long-term functioning.
• Promote community-level plants where single-family units are not feasible, to make use of collective resources.

Q10: Why is energy needed? How can we conserve energy resources? Explain.
Ans: Energy is needed for economic development and daily life in many ways:

• It is required for cooking and heating.
• It provides light and powers electrical appliances.
• It runs machines in industries and powers agricultural equipment.
• It propels vehicles and supports transport, commerce and services.
• Energy is therefore essential for all sectors-agriculture, industry, transport and domestic life-making it central to economic development.

We can conserve energy by the following methods:

• Switch off electrical appliances and lights when not in use.
• Use energy-efficient devices such as LED bulbs and energy-rated appliances.
• Use public transport, car-pooling or non-motorised transport instead of private vehicles.
• Adopt alternative renewable energy sources (solar, wind, biogas) for decentralised and sustainable supply.

Q11: Why is energy required for all activities? How can energy be generated?
Ans: Energy is required for nearly all human activities: to cook food, provide heat and light, propel vehicles, run machines in industries and support agriculture and services. Without energy, modern economic and social systems cannot function effectively.

Energy can be generated from:

• Conventional (non-renewable) sources: firewood, cattle dung cakes, coal, petroleum and natural gas - commonly used for thermal power and transport.
• Non-conventional (renewable) sources: solar, wind, tidal, small hydro and biomass, and energy from waste - these are sustainable and cause less pollution.

Q12: Which is the most abundantly available fossil fuel in India? Mention its different forms.
Ans: The most abundantly available fossil fuel in India is coal. Coal is an important domestic fuel, used for generating thermal power and supplying energy to industries.

Different types of coal and their importance:

• Lignite: A low-grade, brown coal with high moisture content; mainly used for electricity generation in nearby thermal plants.
• Bituminous: A widely used commercial and metallurgical coal formed under higher temperatures; important for power generation and in the production of coke for iron smelting.
• Anthracite: The highest-grade hard coal with high carbon content; used where high heat and a cleaner burn are required, including some industrial and metallurgical applications.

Q13: Explain any three values which inspire us to conserve our energy resources.
Ans: Three values that inspire conservation of energy resources are:

• Environmental responsibility: Saving energy reduces pollution and preserves air, water and soil quality for current and future generations.
• Responsible consumption: Recognising that many energy resources are limited encourages wise and efficient use rather than wasteful habits.
• Intergenerational equity: Conserving energy ensures resources remain available for future generations and supports sustainable development.

Q14: Why is solar energy fast becoming popular in rural and remote areas of India? Explain.
Ans: Solar energy is becoming popular in rural and remote areas for several reasons:

• It is a reliable and abundant source of energy available throughout the year in many parts of India.
• Photovoltaic technology has become more affordable and requires low maintenance, making small installations practical for households.
• Solar power reduces dependence on firewood and dung cakes, helping conserve forests and improving soil fertility by freeing dung for manure.
• Its decentralised nature makes it suitable for remote locations where grid electricity is unavailable or unreliable.

Q15: Which state is the largest producer of manganese in India? Mention any four uses of manganese.
Ans: Odisha is the largest producer of manganese in India.

Four uses of manganese are:

• It is used in the manufacture of steel and ferro-manganese alloys to improve strength and toughness.
• Manganese compounds are used in making bleaching powder and other chemicals.
• It serves as a raw material in certain insecticides and industrial chemicals.
• Manganese compounds are also used in the manufacture of paints and pigments.

Q16: 'Minerals are unevenly distributed in India.' Explain with three examples.
Ans: Minerals in India are not uniformly spread; they occur in specific geological regions. Examples:

• The Peninsular shield (peninsular rocks) contains most of the reserves of coal, many metallic minerals and mica.
• Sedimentary basins in Gujarat and Assam contain rich deposits of petroleum and natural gas, concentrated in particular sedimentary formations.
• Rajasthan and parts of the peninsular region are rich in various non-ferrous minerals, but these occur in specific belts rather than evenly across the country.

Q17: How is energy a basic requirement for the economic development of the country? Explain with examples.
Ans: Energy is fundamental to economic development in the following ways:

• All sectors-agriculture, industry, transport, commerce and households-need energy inputs to operate and grow.
• Planned development projects and industrialisation require steady and increasing supplies of energy to be sustainable.
• For example, coal supplies much of the energy for thermal power plants and industry, while natural gas is an important clean fuel and feedstock for the petrochemical industry.

Q18: Mention any three major iron-ore belts in India. Write any three characteristics of the southernmost iron-ore belt.
Ans: Three major iron-ore belts in India are:

• Orissa-Jharkhand belt
• Durg-Bastar-Chandrapur belt
• Ballari-Chitradurga-Chikkamagaluru-Tumakuru (southern) belt

Three characteristics of the southern-most (Ballari-Chitradurga-Chikkamagaluru-Tumakuru) belt are:

• It contains large reserves of high-grade haematite iron ore, important for steel-making.
• The Kudremukh mines (in the Western Ghats of Karnataka) are notable deposits within this region and have been important for export of iron ore.
• This belt has historically supported local ore-based industries and iron-ore mining, with both export and domestic uses.

Q19: How is solar energy becoming popular in rural and remote areas of India? Explain.
Ans: Solar energy is becoming popular in rural and remote areas because:

• It reduces dependence on firewood and dung cakes, helping conserve forests and improving soil fertility by allowing dung to be used as manure.
• It lowers environmental pollution compared with burning fossil fuels or biomass indoors.
• Solar systems can be installed locally, are often affordable to run, and provide power even in off-grid locations.
• Excess energy can be stored (with batteries) or used for simple applications like lighting, water pumping and small appliances, making life in remote areas easier.

Q20: 'We have to adopt a cautious approach for the judicious use of our limited energy resources.' Support the statement with three examples.
Ans: We must adopt a cautious approach for judicious use of limited energy resources. Three practical examples are:

• Promote public transport and car-pooling to reduce fuel consumption and traffic congestion, thereby saving petrol and diesel.
• Switch to energy-efficient appliances and LED lighting at home and in offices to lower electricity demand.
• Invest in renewable energy systems (solar panels, biogas units) and encourage their use in households and villages to reduce dependence on non-renewable fuels.