Practice Test: Question Set - 03
1. Separators in compressor installations are located
- (A) Before inter-cooler
- (B) After inter-cooler
- (C) After receiver
- (D) Between after-cooler and air receiver
2. Pick up the wrong statement
- (A) Pulse-jet requires no ambient air for
propulsion
- (B) Ramjet engine has no turbine
- (C) Turbine drives compressor in a Turbojet
- (D) Bypass turbojet engine increases the thrust
without adversely affecting, the propulsive efficiency and fuel economy
3. The overall isothermal efficiency of the compressor is defined as the ratio of
- (A) Work
required to compress the air isothermally to the actual work required to
compress the air for the same pressure ratio
- (B) Isothermal
power to the shaft power or B.P. of the motor or engine required to drive the
compressor
- (C) Volume of
free air delivery per stroke to the swept volume of the piston
- (D) Isentropic
power to the power required to drive the compressor
4. Reciprocating air compressor is best suited for
- (A) Large quantity of air at high pressure
- (B) Small quantity of air at high pressure
- (C) Small quantity of air at low pressure
- (D) Large quantity of air
at low pressure
5. In a double acting compressor, the air is compressed
- (A) In one
cylinder
- (B) In two
cylinders
- (C) In a single
cylinder on both sides of the piston
- (D) In two
cylinders on both sides of the piston
6. After-cooler is used to
- (A) Cool the air
- (B) Decrease the delivery temperature for ease
in handling
- (C) Cause moisture and oil vapour to drop out
- (D) Reduce volume
7. Which of the following statement is correct?
- (A) The
reciprocating compressors are best suited for high pressure and low volume
capacity
- (B) The effect
of clearance volume on power consumption is negligible for the same volume of
discharge
- (C) Both (A) and
(B)
- (D) None of
these
8. Mining industry usually employs following motive power
- (A) A.C. electric motor
- (B) Compressed air
- (C) Petrol engine
- (D) Diesel engine
9. The reason for volumetric efficiency of reciprocating compressor being less than 100 percent is
- (A) Pressure
drop across the valves
- (B) Superheating
in compressor
- (C) Clearance
volume and leakages
- (D) All of these
10. In jet propulsion power unit, the inlet duct of diverging shape is used in order to
- (A) Collect more air
- (B) Convert kinetic energy of air into pressure
energy
- (C) Provide robust structure
- (D) Beautify the shape
11. Volumetric efficiency of a compressor without clearance volume
- (A) Increases with increase in compression
ratio
- (B) Decreases with increase in compression
ratio
- (C) Is not dependent upon compression ratio
- (D) May increase/decrease depending on
compressor capacity
12. The mean effective pressure of the compressor is the
- (A) Actual
volume of the air delivered by the compressor when reduced to normal
temperature and pressure conditions
- (B) Volume of
air delivered by the compressor
- (C) Volume of
air sucked by the compressor during its suction stroke
- (D) None of the
above
13. An ideal air compressor cycle without clearance on P-V diagram can be represented by following processes
- (A) One adiabatic, two isobaric, and one
constant volume
- (B) Two adiabatic and two isobaric
- (C) Two adiabatic, one isobaric and one
constant volume
- (D) One adiabatic, one isobaric and two
constant volumes
14. The thrust of a jet propulsion power unit can be increased by
- (A) Injecting
water into the compressor
- (B) Burning fuel
after gas turbine
- (C) Injecting
ammonia into the combustion chamber
- (D) All of the
above
15. Maximum work is done in compressing air when the compression is
- (A) Isothermal
- (B) Adiabatic
- (C) Polytropic
- (D) None of the above
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