Q.1
In a jet engine, the air-fuel ratio is
  • 30:1
  • 40:1
  • 50:1
  • 60:1
Q.2
Free air is the air at
  • Atmospheric conditions at any specific location
  • 20°C and 1 kg/cm² and relative humidity of 36%
  • 0°C and standard atmospheric conditions
  • 15°C and 1 kg/cm²
Q.3
Standard air is the air at
  • Atmospheric conditions at any specific location
  • 20°C and 1 kg/cm² and relative humidity 36%
  • 0°C and standard atmospheric conditions
  • 15°C and 1 kg/cm²
Q.4
In a double acting compressor, the air is compressed
  • In one cylinder
  • In two cylinders
  • In a single cylinder on both sides of the piston
  • In two cylinders on both sides of the piston
Q.5
Gas turbine works on
  • Brayton or Atkinson cycle
  • Carnot cycle
  • Rankine cycle
  • Ericsson cycle
Q.6
An aftercooler is used to
  • remove impurities from air
  • reduce volume of air
  • cause moisture and oil vapour to drop out
  • cool the air
Q.7
The overall efficiency of the compressed air system is the
  • Ratio of shaft output of the air motor to the shaft input to the compressor
  • Ratio of shaft input to the compressor to the shaft output of air motor
  • Product of shaft output of air motor and shaft input to the compressor
  • None of the above
Q.8
The air power of the compressor is also known as
  • Indicated power
  • Brake power
  • Frictional power
  • None of these
Q.9
Which of the following plants is smallest and lightest for generating a given amount of power?
  • Gas turbine plant
  • Petrol engine
  • Diesel engine
  • Solar plant
Q.10
Which of the following plants is smallest and lightest for generating a given amount of power?
  • Gas turbine plant
  • Petrol engine
  • Diesel engine
  • Solar plant
Q.11
The degree of reaction in an axial flow compressor is defined as the ratio of static enthalpy rise in the
  • rotor to static enthalpy rise in the stator
  • stator to static enthalpy rise in the rotor
  • rotor to static enthalpy rise in the stage
  • stator to static enthalpy rise in the stage
Q.12
In a reciprocating air compressor, the compression work per kg of air
  • increases as clearance volume increases
  • decreases as clearance volume increases
  • is independent of clearance volume
  • increases as clearance volume decreases
Q.13
An axial compressor gives optimum performance at high speeds and large volume flows.
  • Agree
  • Disagree
Q.14
The increase in pressure in a roots blower is entirely due to back flow of air.
  • Agree
  • Disagree
Q.15
If pis the pressure of air entering the L.P. cylinder and p2 is the pressure of air leaving the L.P. cylinder (or intercooler pressure), then the ratio of cylinder diameters for a single acting, two stage reciprocating air compressor with complete intercooling is given by (where D1 = Dia. of L.P. cylinder, and D2 = Dia. of H.P. cylinder)
  • D1/D2 = p1p2
  • D1/D2 = p1/p2
  • D1/D2 = p2/p1
  • none of these
Q.16
The ratio of the volume of free air delivery per stroke to the swept volume of the piston, is known as
  • compressor efficiency
  • volumetric efficiency
  • isothermal efficiency
  • mechanical efficiency
Q.17
High air-fuel ratio in gas turbines
  • increases power output
  • improves thermal efficiency
  • reduces exhaust temperature
  • do not damage turbine blades
Q.18
The maximum combustion pressure in gas turbine is __________ as compared to I.C. engine.
  • more
  • less
Q.19
The compression ratio in a gas turbine is
  • 4
  • 1
  • 9
  • 12
Q.20
The actual volume of air delivered by a compressor, When reduced to the normal temperature and pressure conditions is called compressor capacity.
  • Yes
  • No
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