Q.1

The pressure of air at the beginning of the compression stroke is __________ the atmospheric pressure.

  • equal to
  • less than
  • more than
Q.2

In a turbo jet engine, subsequent to heat addition to compressed air, to get the power output, the working substance is expanded in

  • exit nozzle, which is a constant volume process
  • exit nozzle, which is essentially an isentropic process
  • turbine blades, which is a constant volume process
  • turbine blades, which is essentially an isentropic process
Q.3

In a jet engine, the compression varies as the square of the speed.

  • Correct
  • Incorrect
Q.4

A rocket works with maximum overall efficiency when air-craft velocity is __________ the jet velocity.

  • equal to
  • one-half
  • double
Q.5

In jet propulsion power unit, the inlet duct of diverging shape is used for converting kinetic energy of air into pressure energy.

  • True
  • False
Q.6

A receiver in compressor installations is used to damp pressure waves in compressor discharge.

  • Yes
  • No
Q.7

The compressor capacity will be __________ if the temperature of intake air is lowest.

  • lowest
  • highest
Q.8

The perfect intercooling, in multistage compression, means that the temperature of air at inlet to subsequent stages is equal to the initial temperature.

  • Agree
  • Disagree
Q.9

The pressure ratio in a centrifugal compressor can be increased by increasing the tip speed and lowering the inlet temperature.

  • Correct
  • Incorrect
Q.10

The air is delivered __________ in one revolution in case of a three-lobbed rotor.

  • two times
  • three times
  • four times
  • six times
Q.11

In a single acting reciprocating air compressor, without clearance, the compression of air may be

  • isothermal
  • polytropic
  • isentropic
  • any one of these
Q.12

The volumetric efficiency for reciprocating air compressors is about

  • 10 to 40%
  • 40 to 60%
  • 60 to 70%
  • 70 to 90%
Q.13

The maximum temperature in a gas turbine is

  • 200°C
  • 500°C
  • 700°C
  • 1000°C
Q.14

If p1 is the pressure of air entering the L.P, cylinder and p3 is the pressure of air leaving the H.P. cylinder, then the ratio of cylinder diameters for a single acting, two stage reciprocating compressor with complete intercooling is given by

  • D1/D2 = (p1p3)1/2
  • D1/D2 = (p1/p3)1/4
  • D1/D2 = (p1p3)1/4
  • D1/D2 = (p3/p1)1/4
Q.15

Reheating in a gas turbine

  • increases the thermal efficiency
  • increases the compressor work
  • increases the turbine work
  • decreases the thermal efficiency
Q.16

In a single stage, single acting reciprocating air compressor, without clearance, the workdone on the air during isentropic compression is __________ the heat required to raise the temperature of air from T1 to T2 at a constant pressure.

  • equal to
  • less than
  • greater than
Q.17

Workdone by an air compressor __________ upon the way in which the air is compressed.

  • depends
  • does not depend
Q.18

In a compressor, work is done on the piston during suction of air and work is done by the piston during compression as well as delivery of air.

  • Agree
  • Disagree
0 h : 0 m : 1 s