Lignite
Bituminous coal
Semi-anthracite
Anthracite
✅ The correct answer is option B.
Fuel and Combustion MCQs
242. The main reason for making the copper calorimeter (used in bomb calorimeter) silvery white and shining/polished is to
Minimise its corrosion
Avoid radiation heat loss
Make it look attractive
None of these
✅ The correct answer is option B.
243. ‘Fat’ coal means a coal having
Low calorific value
High volatile matter
Low ash content
Non smoking tendency
✅ The correct answer is option B.
244. The maximum adiabatic flame temperature in air is __________ the maximum flame temperature in pure oxygen.
Lower than
Higher than
Same as
Not related to
✅ The correct answer is option A.
245. Coke oven gas burns with an yellowish flame, because of the presence of
CO₂
CH₄
H₂
NH₃
✅ The correct answer is option B.
246. The main advantage of forced draft over natural draft is that
Combustion of fuel is complete
Smaller height chimney can be used
Furnace control is easier
All of the above
✅ The correct answer is option D.
247. Hardgrove grindability index of four coal samples are given below. Which of them is the easiest to grind?
50
70
85
100
✅ The correct answer is option D.
248. Which of the following has the highest flame velocity?
H₂
CO
CH₄
C₂H₆
✅ The correct answer is option A.
249. Dust content in raw blast furnace gas is about __________ gm/Nm³ , hence it is cleaned to the dust level of about < 10 mg /Nm³ before use.
15-30
1-Feb
70-100
150-200
✅ The correct answer is option A.
250. Junker’s calorimeter is used to determine the calorific value of
Pulverised coal
Gaseous fuels
Fuel oil
None of these
✅ The correct answer is option B.