Very Short Answer Type Questions
Question. What is the importance of aluminium ?
Answer : 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.
Question. Why is energy needed ? Write one reason.
Answer : Energy is a basic requirement for economic development. Every sector of the national economy—agriculture, industry, transport, commercial and domestic—needs inputs of energy. It is needed to cook, to provide light and heat, to propel vehicles and to drive machinery in industries.
Question. Which reserves of natural gas have been found in India ?
Answer : Large reserves of natural gas have been discovered in Krishna-Godavari basin. Along the west coast the reserves of the Mumbai high and allied fields are supplemented by findings in the Gulf of Cambay. Andaman and Nicobar islands are also important areas having large reserves of natural gas.
Question. Which are the major iron ore belts in India ?
Answer : The major iron ore belts in India are – (i) Odisha- Jharkhand belt, (ii) Durg-Bastar-Chandrapur belt, (iii) Bellary-Chitrdurga-Chikmaglur-Tumkur and (iv) Maharashtra-Goa belt.
Question. What are rocks made up of ?
Answer : Rocks like Limestone consist of a single mineral only, but a majority of rocks consists of several minerals in varying proportions.
Short Answer Type Questions
Question. ‘‘A concerted effort has to be made in order to use mineral resources in a planned and sustainable manner.‘‘ Suggest and explain any three measures.
Answer : We must make use of minerals in a planned and sustainable manner.
(i) Improved technologies need to be constantly evolved to allow the use of low grade ores at low cost.
(ii) Recycling of metals, using scrap metals and other substitutes are steps in conserving ore mineral resources for the future.
(iii) Try to reuse the waste to reduce the production cost.
Question. Can solar energy solve the energy problem to some extent in India ? Give your opinion.
Answer : In my opinion, solar energy can surely solve the energy problem in India as :
(i) India is a tropical country and has enormous possibilities of tapping solar energy.
(ii) It is expected that use of solar energy can minimize the dependence of rural households on firewood and dung cakes.
(iii) Due to rising prices, serious environmental threats and prolonged replenishment of oil and gas, there is a need to shift to non-conventional sources of energy like solar energy.
Question. Why is conservation of mineral resources essential ? Explain any three reasons.
Answer : Mineral resources which take millions of years to be created and concentrated are being consumed rapidly.
(i) The geological processes 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.
(ii) Rich mineral deposits are our country’s extremely valuable but short-lived possessions.
(iii) Continued extraction of ores leads to increasing costs as extraction comes from greater depths along with decrease in quality.
Question. What are the two main ways of generating electricity ?
Answer : Electricity has such a wide range of application in today’s world that its consumption is considered as an index of development. Electricity is generated mainly in two ways : by running water which drives hydroturbines to generate hydroelectricity; and by burning other fuels such as coal, petroleum and natural gas to drive turbines to produce thermal power.
Question. What do you understand by Tidal energy ? Which area provides suitable conditions for using it ?
Answer : 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 floodgate, 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 Kutch provides ideal conditions for utilising tidal energy. A 900 MW tidal energy power plant is set up here by the National Hydropower Corporation.
Question. What is the difference between hydroelectricity and thermal electricity ?
Answer : (Table 848)
Long Answer Type Questions
Question. Why is there an enormous possibility of tapping solar energy in India ?
Answer. (i) India is blessed with an abundance of sunlight, water, wind and biomass.
(ii) It has the largest programmes for the development of these renewable energy resources. Besides, it is a tropical country. It has possibilities of tapping solar energy.
(iii) Photovoltaic technology converts sunlight directly into electricity. Solar energy is fast becoming popular in rural and remote areas.
(iv) The largest solar plant of India is located at Madhapur near Bhuj, where solar energy is used to sterilise milk.
(v) It is totally harmless and does not pollute the environment. In other words, we can say that it is eco-friendly.
Question. “Minerals are indispensable part of lives.” Support the statement with examples.
OR Why are minerals are indispensable part of our lives ?
Answer : Minerals are indispensable part of our lives because:
(i) From a tiny pin to a towering building or a big ship, almost everything we use today, all are made from minerals.
(ii) The railway lines and the tarmac (paving) of the roads, our implements and machinery too are made from minerals.
(iii) Cars, buses, trains, aeroplanes are manufactured from minerals and run on power resources i.e. petrol and diesel derived from the earth.
(iv) Food that we eat also contains minerals.
(v) Human beings use minerals in all stages of development.
(vi) We use minerals for our livelihood, decoration, festivities, religious and ceremonial rites.
(vii) Toothpaste, we use to clean teeth contain abrasive minerals like silica, limestone, aluminium oxide and various phosphate minerals do the cleaning. Fluoride which is used to reduce cavities comes from a mineral fluorite. The toothbrush and tube containing the paste are made of plastics from petroleum.