Class Notes NCERT Solutions for CBSE Students
Question: 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.
Question: Define quarrying.
Answer: Quarrying is a process of extraction in which minerals lying near the surface are simply dug out.
Question: Name the leading tin producers in Asia.
Answer: China, Malaysia and Indonesia are leading tin producers in Asia.
Question: 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.
Question: Name two minerals in whose production India contributes a significant part.
Answer: India has vast deposits of high grade iron ore, and it is also a leading producer of salt.
Question: In which industry is silicon important? From which ore is it obtained?
Answer: Silicon is important in the computer industry. It is obtained from quartz.
Question: 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.
Question: 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.
Question: 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”.
Question: What is natural gas?
Answer: Natural gas is a fossil fuel obtained with petroleum deposits in oil fields.
Question: Which was the first country to develop hydroelectricity ?
Answer: Norway was the first country to develop hydroelectricity.
Question: Name some important hydel power stations in India.
Answer: Bhakra Nangal, Gandhi Sagar, Nagaijunasagar and Damodar Valley Projects are important hydel power stations in India.
Question: Name nuclear power stations in India.
Answer: Kalpakkam, Tarapur, Ranapratap Sagar, Narora and Kaiga are the nuclear power stations in India.
Question: Give one advantage of biogas over natural gas.
Answer: Biogas is a renewable source of energy whereas the amount of natural gas is limited.
