411. During coal carbonisation process, the conversion of semi-coke to coke is accompanied by an increase in the __________ of the mass.
Density
Porosity
Electrical resistivity
None of these
✅ The correct answer is option A.
Fuel and Combustion MCQs
412. One kg of carbon for theoretically complete combustion requires __________ kg of air.
11.5
0.5
23
12
✅ The correct answer is option A.
413. The shift conversion reaction taking place during water gas manufacture is given by
C + H₂O ⟷ CO + H₂
C + 2H₂O ⟷ CO₂ + 2H₂
CO + H₂O ⟷ CO₂ + H₂
None of these
✅ The correct answer is option C.
414. Insitu theory and drift theory are related to the
Origin of petroleum oil
Origin of coal
Coalification
Variation of coal quality with depth
✅ The correct answer is option B.
415. A coal with high __________ content, would ignite most easily.
Fixed carbon
Volatile matter
Ash
Oxygen
✅ The correct answer is option B.
416. Carbon Content by weight in air dried wood may be about __________ percent.
10
25
50
80
✅ The correct answer is option C.
417. Method of maintaining fires in furnace during standby periods without undue consumption of fuel is called
Back draughting
Banking
Under pressurising
None of these
✅ The correct answer is option B.
418. Percentage of hydrogen in coke oven gas may be around
10
25
45
60
✅ The correct answer is option D.
419. Low temperature oxidation and spontaneous combustion of freshly mined coal is accentuated, if
It contains large amount of volatile matter
It is stored in tall heaps
Smaller fines are stored in large quantity
All of the above
✅ The correct answer is option D.
420. Ignition temperature decreases progressively from anthracite to lignite, because
Volatile matter content increases
Carbon content decreases
Moisture content increases
Ash content increases
✅ The correct answer is option A.