Compressors, Gas Turbines and Jet Engines Objective Questions with Answers - Set 16 - ObjectiveBooks

# Practice Test: Question Set - 16

1. The compressor performance at higher altitude compared to sea level will be
(A) Same
(B) Higher
(C) Lower
(D) Dependent on other factors

2. Pick up the correct statement
(A) Closed cycle gas turbine is an I.C engine
(B) Gas turbine uses same working fluid over and over again
(C) Ideal efficiency of closed cycle gas turbine plant is more than Carnot cycle efficiency
(D) Thrust in turbojet is produced by nozzle exit gases

3. The ratio of the discharge pressure to the inlet pressure of air is called
(A) Compression ratio
(B) Expansion ratio
(C) Compressor efficiency
(D) Volumetric efficiency

4. An air compressor may be controlled by
(A) Throttle control
(B) Clearance control
(C) Blow off control
(D) Any one of the above

5. The minimum work required for a three stage reciprocating air compressor is ________ the work required for each stage.
(A) Equal to
(B) Double
(C) Three times
(D) Six times

6. The air power of the compressor is also known as
(A) Indicated power
(B) Brake power
(C) Frictional power
(D) None of these

7. The compressor capacity with decrease in suction temperature
(A) Increases
(B) Decreases
(C) Remain unaffected
(D) May increase or decrease depending on compressor capacity

8. The maximum propulsion efficiency of a turbojet is attained at around following speed
(A) 550 km/hr
(B) 1050 km/hr
(C) 1700 km/hr
(D) 2400 km/hr

9. In a centrifugal compressor, the flow of air is ________ to the axis of compressor.
(A) Parallel
(B) Perpendicular
(C) Inclined
(D) None of these

10. Aeroplanes employ following type of compressor
(B) Axial flow
(C) Centrifugal
(D) None of the above

11. In a reciprocating air compressor, the compression work per kg of air
(A) Increases as clearance volume increases
(B) Decreases as clearance volume increases
(C) Is independent of clearance volume
(D) Increases as clearance volume decreases

12. The clearance volume of the air compressor is kept minimum because
(A) It allows maximum compression to be achieved
(B) It greatly affects volumetric efficiency
(C) It results in minimum work
(D) It permits isothermal compression

13. Free air is the air at
(A) Atmospheric conditions at any specific location
(B) 20°C and 1 kg/cm² and relative humidity of 36%
(C) 0°C and standard atmospheric conditions
(D) 15°C and 1 kg/cm²

14. In a single stage, single acting reciprocating air compressor, without clearance, the work-done on the air during isentropic compression is ________ the heat required to raise the temperature of air from T₁ to T₂ at a constant pressure.
(A) Equal to
(B) Less than
(C) Greater than
(D) None of these

15. Standard air is the air at
(A) Atmospheric conditions at any specific location
(B) 20°C and 1 kg/cm² and relative humidity 36%
(C) 0°C and standard atmospheric conditions
(D) 15°C and 1 kg/cm²

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