# 250+ TOP MCQs on Air Standard Cycles and Answers

IC Engines Multiple Choice Questions on “Air Standard Cycles”.

1. The air standard efficiency of an I.C. engine depends on _____________
a) fuel used
b) speed of engine
c) compression ratio
d) none of the mentioned
Clarification: None.

2. The specific fuel consumption per B.P. hour for a petrol engine is about ___________
a) 0.2 kg
b) 0.25 kg
c) 0.3 kg
d) 0.35 kg
Clarification: Generally, the specific fuel consumption per B.P. hour for a petrol engine is about 0.25 kg while the specific fuel consumption per B.P. hour for a diesel engine is about 0.2 kg.

3. The specific fuel consumption per B.P. hour for a diesel engine is about ___________
a) 0.2 kg
b) 0.25 kg
c) 0.3 kg
d) 0.35 kg
Clarification: Generally, the specific fuel consumption per B.P. hour for a diesel engine is about 0.2 kg while the specific fuel consumption per B.P. hour for a petrol engine is about 0.25 kg.

4. If the compression ratio in I.C. engine increases, then its thermal efficiency will ___________
a) increase
b) decrease
c) remain same
d) none of the mentioned
Clarification: The compression ratio in I.C. engine is directly proportional to the thermal efficiency, so as it increases, then its thermal efficiency will increase.

5. The thermal efficiency of petrol and gas engines is about ___________
a) 15%
b) 30%
c) 50%
d) 70%
Clarification: The thermal efficiency of petrol and gas engines is about 30% and the thermal efficiency of diesel engines is about 70%.

6. The thermal efficiency of diesel engines is about ___________
a) 15%
b) 30%
c) 50%
d) 70%
Clarification: The thermal efficiency of diesel engines is about 70% while the thermal efficiency of petrol and gas engines is about 30%.

7. The thermal efficiency of diesel engines on weak mixtures is ___________
a) unaffected
b) lower
c) higher
d) dependent on other factors
Clarification: None.

8. The volumetric efficiency of a well designed engine may be ___________
a) 30 to 40%
b) 40 to 60%
c) 60 to 70%
d) 75 to 90%
Clarification: None.

9. The working medium of an air standard cycle has constant ___________ throughout the cycle.
a) pressure
b) volume
c) specific heat
d) mass