1. How much moisture content is present in lignite?
a) 60-75%
b) 10-25%
c) 35-50%
d) 75-100%
Explanation: Lignite moisture can be brought down to a level of 10-15%. Peat can contains 90% moisture in it.
2. From which of the mining technique lignite can be extracted?
a) Open cast mining
b) High wall mining
c) Drift mining
d) Slope mining
Explanation: Open cast mining is used when deposits of commercially used minerals are near the surface of the earth. It is a type of surface process.
3. Which of the following coal have highest volatile matter?
a) Peat
b) Lignite
c) Bituminous
d) Anthracite
Explanation: Lignite burns with long smoky flame which states that it contains high volatile matter. Lignite absorbs oxygen readily on exposure to air
4. What is the time required for the formation of young brown coals?
a) 107 years
b) 3×108 years
c) 3×109 years
d) 1010 years
Explanation: For the formation of matured coals (bituminous and anthracite) 3×108 years are required where as for the young brown coal (peat and lignite) 107 years are required. The temperature for the formation of coal is greater than 300o.
5. Which of the following substance is transformed to coal in its early stage?
a) Animal debris
b) Bacteria
c) Vegetable debris
d) Non-living compounds
Explanation: Vegetable debris is formed by the microbial degradation of dead plants. The bacteria act as an agent is the transformation of vegetable debris into coal and animal debris are converted into petroleum products
6. How is peat directly converted into anthracite by the process of parallel evolution (Hilt’s law)?
a) By maintaining the acid conditions
b) By the process of consolidation and dewatering
c) By the aerobic decay of peat
d) By continuous eliminations of H2 gas
Explanation: When there is continuous elimination of H2 gas, it creates an anaerobic condition due to which there is loss O2 which creates anthracite directly. For aerobic decay, under sedimentary rocks lignite and bituminous coal are formed under different conditions.
7. Which of the following coal contains alternative dull and laminated layers?
a) Cannel coals
b) Banded coals
c) Splint coals
d) Bog-head coals
Explanation: Banded coals are bituminous coals that are identified as vitrain, clarain, durain and fusain. Splint coals are black in colour which burns freely without swelling and cannel coals consist of a greasy lustre
8. Proximate analysis includes the estimation of ash, carbon, hydrogen, sulphur, nitrogen and oxygen.
a) True
b) False
Explanation: Proximate analysis is used for the determination of moisture, volatile matter, ash and fixed carbon. Ultimate analysis is used for the following given purposes.
9. Why is the high percentage of moisture undesirable for coal?
a) It increases the rate of combustion
b) It increases the cost of the coal
c) It reduces the calorific value of coal
d) It decreases its ignition temperature
Explanation: Moisture acts as a barrier in combustion which consequently decreases the calorific value of the coal. Moisture can be removed by drying the coal and the transportation of coal becomes easy.
10. Which of the following component is not a constituent of coal?
a) Moisture
b) Ash
c) Fixed carbon
d) Volatile matter
Explanation: Volatile matter consists of a complex mixture of gaseous and liquid products resulting from the thermal decomposition of the coal. Fixed carbon and ash are constituents of coal where as volatile matter is obtained after the decomposition of coal