101. The optimum percentage of excess air for combustion depends upon the __________ of the fuel.
Type (solid, liquid or gaseous)
Calorific value
Sulphur content
Ignition temperature
✅ The correct answer is option A.
Fuel and Combustion MCQs
102. Cannel coal
Is non-coking
Has a high volatile matter content and burns with a luminous smoky flame
Is a non-banded coal which can be ignited easily with a match stick or candle flame, hence is so named
All of the above
✅ The correct answer is option D.
103. A sooty flame can be made non-luminous by
Admitting more gas
Shutting gas supply
Admitting more air
Shutting air supply
✅ The correct answer is option C.
104. Which of the following constituents of a fuel does not contribute to its calorific value on combustion?
Hydrogen
Sulphur
Carbon
None of these
✅ The correct answer is option D.
105. Which of the following is the most reactive (as regards the formation of CO + H₂ from C + H₂O) ?
Blast furnace coke
Low temperature coke
Anthracite coal
Sub-bituminous coal
✅ The correct answer is option B.
106. A coal containing very high percentage of durain is called __________ coal.
Bright
Splint
Non-banded
Boghead
✅ The correct answer is option B.
107. Very __________ coals are completely devoid of cokability i.e, it is non coking.
Young
Mature
Both A & B
Neither A nor B
✅ The correct answer is option C.
108. Gobar gas constitutes mainly of
CH₄ & CO₂
CO & CO₂
CH₄ & N₂
CO & N₂
✅ The correct answer is option A.
109. Gray-King Assay and Roga Index of coal is a measure of its
Abradability
Grindability
Weathering properties
Caking and swelling properties
✅ The correct answer is option D.
110. In general, the limit of inflammability/explosion limit of fuel gases is widened by the
Increase in gas pressure
Increase in temperature (i.e. preheating)
Use of pure oxygen for combustion instead of air
All of the above
✅ The correct answer is option D.