Applied Thermodynamics 6

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Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Applied Thermodynamics 6

Part 6: List for questions and answers of Applied Thermo dynamics

Q1. The air-fuel ratio in petrol engines is controlled by
a) Controlling valve opening/closing
b) Governing
c) Injection
d) Carburetion

Q2. The function of a distributor in a coil ignition system of I.C. engines is
a) To distribute spark
b) To distribute power
c) To distribute current
d) To time the spark

Q3. The specific fuel consumption per BH hour for a petrol engine is approximately
a) 0.15 kg
b) 0.2 kg
c) 0.25 kg
d) 0.3 kg

Q4. In a four stroke cycle petrol engine, the expansion
a) Starts at top dead center and ends at bottom dead center
b) Starts at 30° before top dead center and ends at 50° before bottom dead center
c) Starts at 30° after top dead center and ends at 50° after bottom dead center
d) May start and end anywhere

Q5. As compared to air standard cycle, in actual working, the effect of variation in specific heats is to
a) Increase maximum pressure and maximum temperature
b) Reduce maximum pressure and maximum temperature
c) Increase maximum pressure and decrease maximum temperature
d) Decrease maximum pressure and increase maximum temperature

Q6.Fuel consumption of diesel engines is not guaranteed at one quarter load because at such low loads
a) The friction is high
b) The friction is unpredictable
c) The small difference in cooling water temperature or in internal friction has a
disproportionate effect
d) The engine is rarely operated

Q7. By higher octane number of spark ignition fuel, it is meant that the fuel has
a) Higher heating value
b) Higher flash point
c) Lower volatility
d) Longer ignition delay

Q8. In diesel engine the diesel fuel injected into cylinder would burn instantly at about compressed air temperature of
a) 250°C
b) 500°C
c) 1000°C
d) 2000°C

Q9. In a petrol engine, the mixture has the lowest pressure at the
a) Beginning of suction stroke
b) End of suction stroke
c) End of compression stroke
d) None of these

Q10. The specific fuel consumption per BHP hour for diesel engine is approximately
a) 0.15 kg
b) 0.2 kg
c) 0.25 kg
d) 0.3 kg

Q11. Which of the following statement is correct?
a) Compression ratio for petrol engines varies from 6 to 10
b) Higher compression ratio in diesel engines results in higher pressures
c) Petrol engines work on Otto cycle
d) All of the above

Q12. All heat engines utilize
a) Low heat value of oil
b) High heat value of oil
c) Net calorific value of oil
d) Calorific value of fuel

Q13. Which of the following statement is wrong?
a) A four stroke cycle engine develops twice the power as that of a two stroke cycle engine
b) For the same power developed, a four stroke cycle engine is lighter, less bulky and occupies less floor area
c) The petrol engines are costly than diesel engines
d) All of the above

Q14. Does the supply of scavenging air at a density greater than that of atmosphere mean engine is supercharged?
a) Yes
b) No
c) To some extent
d) Unpredictable

Q15. In a diesel engine, the fuel is ignited by
a) Spark
b) Injected fuel
c) Heat resulting from compressing air that is supplied for combustion
d) Ignition

Q16. Which of the following does not relate to a spark ignition engine?
a) Ignition coil
b) Spark plug
c) Carburettor
d) Fuel injector

Q17. Compression loss in I.C engines occurs due to
a) Leaking piston rings
b) Use of thick head gasket
c) Clogged air inlet slots
d) All of the above

Q18. A two stroke cycle engine gives ________ the number of power strokes as compared to the four stroke cycle engine, at the same engine speed
a) Half
b) Same
c) Double
d) Four times

Q19. The accumulation of carbon in a cylinder results in increase of
a) Clearance volume
b) Volumetric efficiency
c) Ignition time
d) Effective compression ratio

Q20. In a four stroke cycle engine, the sequence of operations is
a) Suction, compression, expansion and exhaust
b) Suction, expansion, compression and exhaust
c) Expansion, compression, suction and exhaust
d) Compression, expansion, suction and exhaust

Part 6: List for questions and answers of Applied Thermo dynamics

Q1. Answer: d

Q2. Answer: d

Q3. Answer: c

Q4. Answer: b

Q5. Answer: b

Q6. Answer: c

Q7. Answer: d

Q8. Answer: c

Q9. Answer: b

Q10. Answer: b

Q11. Answer: d

Q12. Answer: a

Q13. Answer: d

Q14. Answer: b

Q15. Answer: c

Q16. Answer: d

Q17. Answer: d

Q18. Answer: c

Q19. Answer: d

Q20. Answer: a