HSC Arts (English Medium) इयत्ता १२ वी - Maharashtra State Board Question Bank Solutions for Geography

Coal is a black or gray rock by colour. Coal is made of carbon. Coal formation is due to the fact that plant remains have been buried underground millions of years ago. Coal production has been extensive in the Carboniferous era. This period is 300 million years old. According to geologists, in the Carboniferous era, coal was produced in wetlands where temperate forest growth occurs. Remains of dead plants such as bunds and branches are stored in the wetlands and over time due to the accumulation of silt and mud on them, the plant does not rot completely due to the weight of the silt. Plant remains are suppressed by pressure from the sediment, as well as by the movements of the earth's crust, and sometimes by the heat of the volcano. This causes chemical and physical changes in the buried plant layer, which is initially converted to peat (crude coal) and then to other types of coal. There are many types of coal, depending on the composition of the coal and the amount of carbon. There are four types of coal based on the amount of carbon in the coal: Anthracite, bituminous, lignite, peat etc.

Coal is used as a fuel in thermal power generation. In many parts of the world, coal is used to generate water vapour over heat. Coal is also used as a fuel in steam engines of ships and trains. After power generation, coal is mostly used in the steel industry. Coal is used as fuel in the cement industry. Many types of chemicals are produced from the coal component. E.g. Asphalt, fennel, benzole, plastics, dyes, disinfectants, fertilizers, etc. The gas produced from coal is used to make bio-chemicals. Even today, coal is used as a fuel for cooking and keeping the house warm.