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
- (A) Radial flow
- (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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