Fuels and Combustion

361.The main reason for making the copper calorimeter (used in bomb calorimeter) silvery white and shining/polished is to

1. Minimise its corrosion
2. Avoid radiation heat loss
3. Make it look attractive
4. None of these

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362.The maximum adiabatic flame temperature in air as compared to that in pure oxygen is

1. Much lower
2. Much higher
3. Same
4. Either lower or higher, depends on the type of fuel

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363.The maximum adiabatic flame temperature in air is _________ the maximum flame temperature in pure oxygen.

1. Lower than
2. Higher than
3. Same as
4. Not related to

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364.The maximum adiabatic flame temperature is attained, when the fuel is burnt with

1. Theoretically required amount of air
2. More than theoretically required amount of air
3. Less than theoretically required amount of air
4. Theoretically required amount of oxygen

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365.The maximum percentage of CO₂ in a flue gas (from a carbonaceous fuel) can be

1. 21
2. 77
3. 79
4. 29

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366.The most matured coal out of the following is

1. Lignite
2. Semi-anthracite
3. Sub-bituminous
4. Bituminous

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367.The optimum percentage of excess air for combustion depends upon the _________ of the fuel.

1. Type (solid, liquid or gaseous)
2. Calorific value
3. Sulphur content
4. Ignition temperature

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368.The pyrogallol solution used in Orsat apparatus can absorb

1. Only O₂
2. Both O₂ and CO₂
3. Both O₂ and CO
4. All CO, CO₂, and O₂

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369.The ratio of % total carbon obtained in the ultimate analysis of coke and % fixed carbon obtained in the proximate analysis is always

1. 1
2. < 1
3. > 1
4. Unpredictable

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370.The ratio of maximum adiabatic flame temperature in air to that in pure oxygen is always

1. 1
2. < 1
3. > 1
4. Unpredictable

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