# Practice Test: Question Set - 11

1. A compressor at high altitudes will require ________ power.
(A) Same
(B) Less
(C) More
(D) None of these

2. Pick up the wrong statement
(A) Centrifugal compressors deliver practically constant pressure over a considerable range of capacities
(B) Axial flow compressors have a substantially constant delivery at variable pressures
(C) Centrifugal compressors have a wider stable operating range than axial flow compressors
(D) Axial flow compressors are bigger in diameter compared to centrifugal type

3. The compression ratio for the compressor is always _________ unity.
(A) Equal to
(B) Less than
(C) More than
(D) None of these

4. The work ratio of a gas turbine plant is defined as the ratio of
(A) Net work output and heat supplied
(B) Net work output and work done by turbine
(C) Actual heat drop and isentropic heat drop
(D) Net work output and isentropic heat drop

5. Euler's equation can be used for
(B) Axial flow compressors
(C) Pumps
(D) All of these

6. Gas turbine works on
(A) Brayton or Atkinson cycle
(B) Carnot cycle
(C) Rankine cycle
(D) Ericsson cycle

7. The ratio of the indicated power to the shaft power or brake power of the motor or engine required to drive the compressor, is called
(A) Compressor efficiency
(B) Volumetric efficiency
(C) Isothermal efficiency
(D) Mechanical efficiency

8. The work ratio of simple gas turbine cycle depends on
(A) Pressure ratio
(B) Maximum cycle temperature
(C) Minimum cycle temperature
(D) All of the above

9. The efficiency of a jet engine is higher at
(A) Low speeds
(B) High speeds
(C) Low altitudes
(D) High altitudes

10. The pressure ratio for an open cycle gas turbine compared to closed cycle gas turbine of same h.p. is
(A) Low
(B) High
(C) Same
(D) Low/high depending on make and type

11. In a single acting reciprocating compressor, the suction, compression and delivery of air takes place in ________ of the piston.
(A) One stroke
(B) Two strokes
(C) Three strokes
(D) Four strokes

12. Open cycle gas turbine works on
(A) Brayton or Atkinson cycle
(B) Rankine cycle
(C) Carnot cycle
(D) Ericsson cycle

13. Which of the following statement is wrong?
(A) In a two stage reciprocating air compressor with complete intercooling, maximum work is saved
(B) The minimum work required for a two stage reciprocating air compressor is double the work required for each stage
(C) The ratio of the volume of free air delivery per stroke to the swept volume of the piston is called volumetric efficiency
(D) None of the above

14. The fuel consumption in gas turbines is accounted for by
(A) Lower heating value
(B) Higher heating value
(C) Heating value
(D) Higher calorific value

15. The degree of reaction in an axial flow compressor is defined as the ratio of static enthalpy rise in the
(A) Rotor to static enthalpy rise in the stator
(B) Stator to static enthalpy rise in the rotor
(C) Rotor to static enthalpy rise in the stage
(D) Stator to static enthalpy rise in the stage

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