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.
Explanation: compression ratio
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
Explanation: 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
Explanation: 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
Explanation: 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%
Explanation: 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%
Explanation: 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
Explanation: The thermal efficiency of diesel engines on weak mixtures is higher
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%
Explanation: 75 to 90%
9. The working medium of an air standard cycle has constant ___________ throughout the cycle.
a) pressure
b) volume
c) specific heat
d) mass
Explanation: specific heat
10. It is assumed that all the processes of an air standard cycle are _____
a) reversible
b) irreversible
c) adiabatic
d) isothermal
Explanation : It is assumed that all the processes of an air standard cycle are reversible