61. A particular coal is said to be free burning when it
Burns completely
Gives smokeless burning
Shows little or no fusing action
None of these
✅ The correct answer is option C.
Fuel and Combustion MCQs
62. The difference between total carbon and fixed carbon of coal will be minimum in case of
Lignite
Bituminous coal
Anthracite
High temperature coke (V.M < 0.5%)
✅ The correct answer is option D.
63. A coal containing high amount of volatile matter will have
Low ignition temperature
Very little ash content
High fusion point of its ash
Low adiabatic flame temperature
✅ The correct answer is option A.
64. Oxygen required for theoretically complete combustion of 1 Nm³ methane is __________ Nm³.
2
4
6
1
✅ The correct answer is option A.
65. Bunsen burner is an example of a/an __________ burner.
Inside mixing/premix type
Outside mixing/diffusion flame/nozzle mix type
Rotary cup
Submerged combustion
✅ The correct answer is option A.
66. Blast furnace coke is made from coal by
Low temperature carbonisation
High temperature carbonisation
Medium temperature carbonisation
Heating the coal in an oven in presence of air
✅ The correct answer is option B.
67. Height of coke oven is limited (say maximum upto 7 metres) mainly by the
Problem of uniform heating along its height
Structural strength of silica bricks
Problem in door cleaning
Buckling of ram of pusher car at the time of coke pushing
✅ The correct answer is option A.
68. Efficiency of the combustion of a fuel is judged by the __________ the flue gas.
%of CO₂ in
% of O₂in
Temperature of
Colour of
✅ The correct answer is option B.
69. Preheating of coal charge for the coke ovens reduces the
Time of carbonisation
Yield of gas and tar
Fuel consumption in coking
All of the above
✅ The correct answer is option D.
70. Deficiency of combustion air during combustion of a gaseous fuel
Lengthens the flame
Causes heat loss of fuel by its partial combustion
Both A & B
Shortens the flame
✅ The correct answer is option C.