Related Questions

Spontaneous combustion of coal on storage results due to
A Inadequate ventilation
B Low temperature oxidation
C Storage in large heaps with small surface to volume ratio
D All of the above
To avoid fire by spontaneous combustion of coal due to its low temperature oxidation, it should be stored in
A Shallow and small piles
B Fine sizes without the presence of any lump
C Closed space without any ventilation facility
D Large heaps with small surface to volume ratio
Which one of the following processes of weathering belongs to both mechanical and chemical weathering?
A Crystallization
B Exfoliation
C Hydration
D Carbonation
Low temperature oxidation and spontaneous combustion of freshly mined coal is accentuated, if
A It contains large amount of volatile matter
B It is stored in tall heaps
C Smaller fines are stored in large quantity
D All of the above
Weathering of coal during storage causes
A Reduction in coal size
B Increase in its friability
C Decrease in its caking capacity
D All of the above
Use of excess of combustion air in the combustion of fuels results in
A Heat losses
B Long flame
C Condensation of water vapour from the fuel gas
D None of these
In electrical resistance welding, distortion results from the use of improper
A Clamping methods
B Electrodes
C Current
D Filler material
Combustion of pulverised coal as compared to that of lump coal
A Develops a non-luminous flame
B Develops a low temperature flame
C Can be done with less excess air
D Provides a lower rate of heat release
Combustion of pulverised coal compared to the lumpy coal
A Provides better control of furnace temperature
B Facilitates combustion with lower excess air
C Provides higher thermal efficiency & flame temperature
D All of the above
Pre-ignition is caused by the spontaneous combustion of the mixture before the end of the compression stroke, and is due to
A Cylinder walls being too hot
B Overheated spark plug points
C Red hot carbon deposits on cylinder walls
D Any one of these

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