SECTION -3 
COMPRESSORS, GAS TURBINES AND JET ENGINES MCQ
 
Q71. Work input to the air compressor with ‘n’ as index of compression

(a) increases with increase in value of n 
(b) decreases with increase in value of n 
(c) remains same whatever the value of n 
(d) first increases and then decreases with increase of value of n. 

Ans:(a) increases with increase in value of n

 

Q72. The air fuel ratio in a jet engine is

(a) 10 : 1 
(b) 40 : 1 
(c) 60 : 1 
(d) 90 : 1.

Ans:(c) 60 : 1

 

Q73. In a two-stage gas turbine plant reheating after first stage

(a) decreases thermal efficiency 
(b) increases thermal efficiency 
(c) does not effect thermal efficiency 
(d) none of the above. 

Ans:(a) decreases thermal efficiency

 

Q74. In a two-stage gas turbine plant, reheating after first stage

(a) increases work ratio 
(b) decreases work ratio 
(c) does not affect work ratio 
(d) none of the above. 

Ans:(a) increases work ratio

 

Q75. For the least work to be done on a compressor, the compression should be

(a) adiabatic 
(b) isothermal 
(c) polytropic 
(d) none of the above.

Ans:(b) isothermal

 

Q76. In multi-stage compression as compared to single stage compression, the volumetric efficiency is

(a) more 
(b) less 
(c) constant 
(d) none of the above. 

Ans:(a) more

 

Q77. The ratio of specific weight per h.p. of I.C. engine and gas turbines is of the order of

(a) 6 : 1 
(b) 1 : 4 
(c) 2 : l 
(d) 3 : l. 

Ans:(a) 6 : 1

 

Q78. For a given inlet temperature, the thermal efficiency of a simple gas turbine with increase in pressure ratio

(a) decreases 
(b) increases 
(c) first increases then decreases 
(d) remains constant.

Ans:(c) first increases then decreases

 

Q79. A simple gas turbine cycle will have more efficiency and more work if

(a) multi-stage compressor with intercoolers are used 
(b) heat exchangers are used 
(c) the air partial expansion in the turbine is reheated 
(d) all of the above. 

Ans:(d) all of the above.

 

Q80. In a two-stage gas turbine plant, with intercooling and reheating

(a) both work ratio and thermal efficiency improve 
(b) work ratio improves but thermal efficiency decreases 
(c) thermal efficiency improves but work ratio decreases 
(d) both work ratio and thermal efficiency decrease.

Ans:(b) work ratio improves but thermal efficiency decreases

 

 

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Each section contains maximum 80 Questions. To practice more questions visit other sections.
 
Compressors, Gas turbines and Jet Engines – Section-1
 
Compressors, Gas turbines and Jet Engines – Section-2
 
Compressors, Gas turbines and Jet Engines – Section-3
 

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