Chapter 3, Minerals and Power Resources
CBSE Class 8 NCERT Geography - Resources and Development
Important Terms and Definitions
Mineral: Mineral is a natural chemical compound, uniform in compositions and structure and is a constituent of rocks and ores.
Mining: Mining is the process of extracting minerals from rocks buried under the earth surface. There are two types of mining - Open cast mining and Shaft mining.
Open cast mining: The process of taking out minerals from rocks buried under the surface of the earth at shallow depths by removing the over-burden (surface layer) is known as Open cast mining. Open cast mines of coal can be seen in Raniganj (West Bengal) and Singrauli (MP).
Shaft mining: The process of taking out minerals from great depths through deep bores called shafts is known as Shaft mining. In Jharia - Dhanbad belt (Jharkhand) we find coal mining is being done through this process.
Quarrying: Process of digging out of minerals from shallow depths under the surface is known as Quarrying. For examples, Limestone, Quartzite etc are taken out through this process.
Drilling: Deep bores made for taking out petroleum and natural gas are termed as drilling. In other words it is the process by which we extract oil and natural gas from oil wells which occur in sedimentary rocks.
CBSE Guide (Solutions of CBSE extra questions)
Question.1: Give an account of Biogas.
Answer: Organic wastes like dead plant and animal materials, animal dung kitchen wastes are converted into a gaseous fuel called biogas. The organic waste is decomposed by bacteria in biogas digesters to emit biogas. It is a mixture of carbon-dioxide and methane. Biogas is an excellent fuel for cooking and lighting. Moreover, biogas plants produce a huge amount of manure each year.
Question.2: How is geothermal energy used?
Answer: Heat energy obtained from earth is called geothermal energy. The temperature in the interior of earth increases with the increase of depth. This heat energy comes to the surface of the earth in the form of hot springs which can be used for various purposes like - to generate power, for cooking and also bathing. It is believed that bathing in hot springs heal many diseases. In India geothermal power are located in Manikaran (Himachal Pradesh) and Puga valley (Ladakh). Geothermal power is also found in other parts of the world e.g. USA, New Zealand, Iceland, Central America and Philippines.
* Minerals and Power Resources - NCERTanswers CBSE Class 8 Geography - Chapter 3, Resources and Development
* NCERT Solutions, CBSE Guide, Notes, CBSEextra questions for Class 8 Geography textbook – Resources and Development (allchapters)