Q.1
The rotary compressors are suitable for large discharge of air at low pressure.
  • True
  • False
Q.2
The volumetric efficiency for reciprocating air compressors is about
  • 10 to 40%
  • 40 to 60%
  • 60 to 70%
  • 70 to 90%
Q.3
A rocket works with maximum overall efficiency when air-craft velocity is __________ the jet velocity.
  • equal to
  • one-half
  • double
Q.4
The compressed air may be used
  • in gas turbine plants
  • for operating pneumatic drills
  • in starting and supercharging of I. engines
  • all of the above
Q.5
In a four stage compressor, if the pressure at the first and third stage are 1 bar andbar, then the delivery pressure at the fourth stage will be
  • 1 bar
  • 16 bar
  • 64 bar
  • 256 bar
Q.6
The reason for volumetric efficiency of reciprocating compressor being less thanpercent is
  • Pressure drop across the valves
  • Superheating in compressor
  • Clearance volume and leakages
  • All of these
Q.7
The work-done on a compressor will be minimum if air is taken from
  • The atmosphere
  • A source at 0° C
  • A source of low temperature air
  • A source of high temperature air
Q.8
The maximum delivery pressure in a rotary air compressor is
  • 10 bar
  • 20 bar
  • 30 bar
  • 50 bar
Q.9
Propulsion efficiency of the following order is obtained in practice
  • 34%
  • 50%
  • 60%
  • 72%
Q.10
The type of rotary compressor used in aeroplanes, is of
  • Centrifugal type
  • Axial flow type
  • Radial flow type
  • None of these
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