Applied Thermodynamics 3

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Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Applied Thermodynamics 3

Part 3: List for questions and answers of Applied Thermo dynamics

Q1. If the temperature of intake air in internal combustion engine increases, then its efficiency will
a) Remain same
b) Decrease
c) Increase
d) None of these

Q2. The operation of forcing additional air under pressure in the engine cylinder is known as
a) Scavenging
b) Turbulence
c) Supercharging
d) Pre-ignition

Q3. The ignition quality of petrol is expressed by
a) Cetane number
b) Octane number
c) Calorific value
d) All of these

Q4. The mean effective pressure obtained from engine indicator indicates the
a) Maximum pressure developed
b) Minimum pressure
c) Instantaneous pressure at any instant
d) Average pressure

Q5. The probability of knocking in diesel engines is increased by
a) High self ignition temperature
b) Low volatility
c) Higher viscosity
d) All of these

Q6. The maximum temperature in the I.C. engine cylinder is of the order of
a) 500-1000°C
b) 1000-1500°C
c) 1500-2000°C
d) 2000-2500°C

Q7. In compression ignition engines, swirl denotes a
a) Haphazard motion of the gases in the chamber
b) Rotary motion of the gases in the chamber
c) Radial motion of the gases in the chamber
d) None of the above

Q8. Supercharging is the process of
a) Supplying the intake of an engine with air at a density greater than the density of the surrounding atmosphere
b) Providing forced cooling air
c) Injecting excess fuel for raising more loads
d) Supplying compressed air to remove combustion products fully

Q9. The knocking in spark ignition engines can be reduced by
a) Retarding the spark
b) Increasing the engine speed
c) Both (A) and (B)
d) None of these

Q10. An engine indicator is used to determine the following
a) Speed
b) Temperature
c) Volume of cylinder
d) M.E.P. And I.H.P

Q11. The pressure at the end of compression in the case of diesel engine is of the order of
a) 6 kg/cm
b) 12 kg/cm
c) 20 kg/cm
d) 35 kg/cm

Q12. The fuels in order of decreasing knock tendency for spark ignition engines are
a) Paraffin, aromatic, napthene
b) Paraffin, napthene, aromatic
c) Napthene, aromatics, paraffin
d) Napthene, paraffin, aromatic

Q13. The air requirement of a petrol engine during starting compared to theoretical air required for complete combustion is
a) More
b) Less
c) Same
d) May be more or less depending on engine capacity

Q14. It the temperature of intake air in IC engines is lowered, then its efficiency will
a) Increase
b) Decrease
c) Remain same
d) Increase up to certain limit and then decrease

Q15. The loud pulsating noise heard within the cylinder of an internal combustion engine is known as
a) Detonation
b) Turbulence
c) Pre-ignition
d) Supercharging

Q16. Which of the following medium is compressed in a Diesel engine cylinder?
a) Air alone
b) Air and fuel
c) Air and lub oil
d) Fuel alone

Q17. A stoichiometric air-fuel ratio is
a) Chemically correct mixture
b) Lean mixture
c) Rich mixture for idling
d) Rich mixture for over loads

Q18. The firing order in an I.C. engine depends upon
a) Arrangement of the cylinders
b) Design of crankshaft
c) Number of cylinders
d) All of these

Q19. Pick up the false statement
a) Thermal efficiency of diesel engine is about 34%
b) Theoretically correct mixture of air and petrol is approximately 15:1
c) High speed compression engines operate on dual combustion cycle
d) S.I. engines are quality governed engines

Q20. The maximum propulsive efficiency of a turbojet engine is at a speed of
a) 1000 km/h
b) 2000 km/h
c) 2400 km/h
d) 3000 km/h

Part 3: List for questions and answers of Applied Thermo dynamics

Q1. Answer: b

Q2. Answer: c

Q3. Answer: b

Q4. Answer: d

Q5. Answer: d

Q6. Answer: d

Q7. Answer: b

Q8. Answer: a

Q9. Answer: c

Q10. Answer: d

Q11. Answer: d

Q12. Answer: b

Q13. Answer: b

Q14. Answer: a

Q15. Answer: a

Q16. Answer: a

Q17. Answer: a

Q18. Answer: d

Q19. Answer: d

Q20. Answer: c