- (A) infinitely long
- (B) around 200 meters
- (C) equal to the height of the hot gas column producing draught
- (D) outside temperature is very low
- (E) more than the tallest building nearby
Mechanical Engineering Mcqs
- (A) it has heating value
- (B) it helps in electrostatic precipitation of ash in flue-gases
- (C) it leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low
- (D) it erodes furnace walls
- (E) none of the above
- (A) inherent moisture and surface mois¬ture are different things
- (B) in some coals moisture may be present upto 40%
- (C) some moisture in coal helps in better burning which is not possible with completely dry coal
- (D) it increases thermal efficiency
- (E) moisture in coal is removed before firing by heating it with hot air
- (A) to provide proper conditions for con-tinuous complete combustion
- (B) mix fuel with air and ignite
- (C) separate ash from coal
- (D) maintain heat supply to prepare and ignite the incoming fuel
- (E) to minimise radiation losses
- (A) high burning rate is possible
- (B) heat release can be easily controlled
- (C) fuel burns economically
- (D) it is the best technique for burning high ash content fuel having low fusion ash
- (E) separate mills are required to powder the coal
- (A) high calorific value
- (B) produce minimum smoke and gases
- (C) ease in storing
- (D) high ignition point
- (E) ecomomical
- (A) 15%
- (B) 20%
- (C) 30%
- (D) 45%
- (E) 60%.
- (A) one-fourth
- (B) half
- (C) one
- (D) two
- (E) three
- (A) boiler efficiency, turhine efficiecny, generator efficiency
- (B) all the three above plus gas cycle efficiency
- (C) carnot cycle efficiency
- (D) regenerative cycle efficiency
- (E) rankine cycle efficiency
- (A) heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
- (B) water is supplied in drum and through down-comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam
- (C) feed pump is employed to supplement natural circulation in water wall type furnace
- (D) water is converted into steam in one pass without any recirculation
- (E) water is heated in a large number of tubes
