Applied Thermodynamics 4

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Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Applied Thermodynamics 4

Part 4: List for questions and answers of Applied Thermo dynamics

Q1. The ratio of indicated thermal efficiency to the corresponding air standard cycle efficiency is called
a) Net efficiency
b) Efficiency ratio
c) Relative efficiency
d) Overall efficiency

Q2. The inlet valve of a four stroke cycle internal combustion engine remains open for
a) 130°
b) 180°
c) 230°
d) 270°

Q3. The minimum cranking speed in case of petrol engine is about
a) Half the operating speed
b) One fourth of operating speed
c) 250 – 300 rpm
d) 60 – 80 rpm

Q4. Number of working strokes per min. For a two stroke cycle engine is _________ the speed of the engine in r.p.m
a) Equal to
b) One-half
c) Twice
d) Four-times

Q5. In petrol engines, advancing of the spark timing will _________ the knocking tendency
a) Not effect
b) Decrease
c) Increase
d) None of these

Q6. In a naturally aspirated diesel engine, the air is supplied by
a) A supercharger
b) A centrifugal blower
c) A vacuum chamber
d) An injection tube

Q7. A supercharged engine as compared to an ordinary engine
a) Requires smaller foundation
b) Is lighter
c) Consumes less lubricating oil
d) All of these

Q8. Which of the following is not an intern’s combustion engine?
a) 2-stroke petrol engine
b) 4-stroke petrol engine
c) Diesel engine
d) Steam turbine

Q9. The spark ignition engines are governed by
a) Hit and miss governing
b) Qualitative governing
c) Quantitative governing
d) Combination of (B) and (C)

Q10. Diesel engine can work on very lean air fuel ratio of the order of 30: 1. A petrol engine can also work on such a lean ratio provided
a) It is properly designed
b) Best quality fuel is used
c) Cannot work as it is impossible
d) Flywheel size is proper

Q11. The object of providing masked inlet valve in the air passage of compression ignition engines is to
a) Enhance flow rate
b) Control air flow
c) Induce primary swirl
d) Induce secondary turbulence

Q12. In the crankcase method of scavenging, the air pressure is produced by
a) Supercharger
b) Centrifugal pump
c) Natural aspirator
d) Movement of engine piston

Q13. The temperature of interior surface of cylinder wall in normal operation is not allowed to exceed
a) 80°C
b) 120°C
c) 180°C
d) 240°C

Q14. Thermal efficiency of a two stroke cycle engine is _________ a four stroke cycle engine
a) Equal to
b) Less than
c) Greater than
d) None of these

Q15. Scavenging is usually done to increase
a) Thermal efficiency
b) Speed
c) Power output
d) Fuel consumption

Q16. The pressure and temperature at the end of compression stroke in a petrol engine are of the order of
a) 4-6 kg/cm² and 200-250°C
b) 6-12 kg/cm² and 250-350°C
c) 12-20 kg/cm² and 350-450°C
d) 20-30 kg/cm² and 450-500°C

Q17. The compression ignition engines are governed by
a) Hit and miss governing
b) Qualitative governing
c) Quantitative governing
d) Combination of (B) and (C)

Q18. The reason for supercharging in any engine is to
a) Increase efficiency
b) Increase power
c) Reduce weight and bulk for a given output
d) Effect fuel economy

Q19. Stoichiometric ratio is
a) Chemically correct air-fuel ratio by weight
b) Chemically correct air-fuel ratio by volume
c) Actual air-fuel ratio for maximum efficiency
d) None of the above

Q20. The ratio of the volume of charge admitted at N.T.P. to the swept volume of the piston is called
a) Mechanical efficiency
b) Overall efficiency
c) Volumetric efficiency
d) Relative efficiency

Part 4: List for questions and answers of Applied Thermo dynamics

Q1. Answer: c

Q2. Answer: c

Q3. Answer: d

Q4. Answer: a

Q5. Answer: c

Q6. Answer: c

Q7. Answer: d

Q8. Answer: d

Q9. Answer: c

Q10. Answer: a

Q11. Answer: c

Q12. Answer: d

Q13. Answer: c

Q14. Answer: b

Q15. Answer: c

Q16. Answer: b

Q17. Answer: b

Q18. Answer: c

Q19. Answer: b

Q20. Answer: c