Practice Test: Question Set - 06
1. The capacity of a compressor is expressed in
- (A) kg/m²
- (B) kg/m³
- (C) m³/min
- (D) m³/kg
2. The work done per unit mass of air in compression will be least when 'n' is equal to
- (A) 1
- (B) 1.2
- (C) 1.3
- (D) 1.4
3. Cylinder clearance in a compressor should be
- (A) As large as possible
- (B) As small as possible
- (C) About 50% of swept volume
- (D) About 100% of swept volume
4. The ratio of work-done per cycle to the stroke volume of the compressor is known as
- (A) Compressor
capacity
- (B) Compression
ratio
- (C) Compressor
efficiency
- (D) Mean
effective pressure
5. Ratio of compression is the ratio of
- (A) Gauge discharge
pressure to the gauge intake pressure
- (B) Absolute discharge
pressure to the absolute intake pressure
- (C) Pressures at
discharge and suction corresponding to same temperature
- (D) Stroke volume and clearance volume
6. The compressed air may be used
- (A) In gas
turbine plants
- (B) For
operating pneumatic drills
- (C) In starting
and supercharging of I.C. engines
- (D) All of the
above
7. The net work input required for compressor with increase in clearance volume
- (A) Increases
- (B) Decreases
- (C) Remains same
- (D) Increases/decreases
depending on compressor capacity
8. For minimum work required to compress and deliver a quantity of air by multistage compression
- (A) The
compression ratio in each stage should be same
- (B) The
intercooling should be perfect
- (C) The
work-done in each stage should be same
- (D) All
of the above
9. Ratio of indicated h.p. to shaft h.p. in known as
- (A) Compressor efficiency
- (B) Isothermal efficiency
- (C) Volumetric efficiency
- (D) Mechanical efficiency
10. In a jet engine, the air-fuel ratio is
- (A) 30:1
- (B) 40:1
- (C) 50:1
- (D) 60:1
11. Volumetric efficiency is
- (A) The ratio of stroke
volume to clearance volume
- (B) The ratio of the air
actually delivered to the amount of piston displacement
- (C) Reciprocal of
compression ratio
- (D) Index of compressor
performance
12. In axial flow compressor, exit flow angle deviation from the blade angle is a function of
- (A) Blade
camber
- (B) Blade
camber and incidence angle
- (C) Space-chord
ratio
- (D) Blade
camber and space-chord ratio
13. Volumetric efficiency of air compressors is of the order of
- (A) 20 - 30%
- (B) 40 - 50%
- (C) 60 - 70%
- (D) 70 - 90%
14. The velocity of air entering in a rocket is _________ as compared to an aircraft.
- (A) Zero
- (B) Less
- (C) More
- (D) Same
15. Volumetric efficiency of a compressor with clearance volume
- (A) Increases with
increase in compression ratio
- (B) Decreases with
increase in compression ratio
- (C) In not dependent upon
compression ratio
- (D) May increase/decrease
depending on compressor capacity
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