Gas Turbines and Jet Engines Online Quiz Practice Test1

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1. 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

2. 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

3. 1 m of air at atmospheric condition weighs approximately
0.5 kg	1.0 kg
1.3 kg	2.2 kg

4. Adiabatic compression is one in which ____.
temperature during compression remains constant	no heat leaves or enters the compressor cylinder during cornpression
temperature rise follows a linear relationship	work done is maximum

5. The capacity of a compressor is 5 m /mih. 5 m /min refers to
standard air	free air
compressed air	compressed air at delivery pressure

6. The overall isothermal eiffciency of compressor is defined as the ratio of _____.
isothermal h.p. to the BHP of motor	isothermal h.p. to adiabatic h.p.
power to drive compressor to isothermal h.p.	work to compress air isothermally to work for actual compression

7. The most efficient method of compressing air is to compress it
isothermally	adiabatically
isentropically	isochronically

8. Maximum work is done in compressing air when the compression is
isothermal	adiabatic
polytropic	any one of the above

9. The pressure and temperature conditions of air at the suction of compressor are
atmospheric	slightly more than atmospheric
slightly less than atmospheric	pressure sightly less than atmospheric and temperature slightly more than atmospheric.

10. Isothermal compression effeicency can be attained by running the compressor
at very high speed	at very slow speed
at average speed	at zero speed

11. The compressor capacity with decrease in suction temperature
increases	decreases
remains unaffected	may increase or decrease depending on compressor capacity

12. Isothermal compression efficiency, even when running at high speed, can be approached by using
multi-stage compression	cold water spray
both (a) and (b)	fully insulating the cylinder

13. Compression efficiency is compared against
ideal compression	adiabatic compression
botii isothermal and adiabatic compression	isothermal compression

14. Aeroplanes employ following type of compressor
radial flow	axial flow
centrifugal	combination of above

15. Inter cooling in compressors
cools the delivered air	results in saving of power in compressing a given volume to given pressure
is the standard practice for big com-pressors	enables compression in two stages

16. An ideal air compressor cycle without clearance on p-v diagram can be represented by following processes
one adiabatic, two isobaric, and one constant volume	two adiabatic and two isobaric
two adiabatic, one isobaric and one constant volume	one adiabatic, one isobaric and two constant volume

17. An ideal air compressor cycle with clearance on p-v diagram can be represented by following processes
one adiabatic, two isobaric, and one constant volume	two adiabatic and two isobaric
two adiabatic, one isobaric and one constant volume	one adiabatic, one isobaric and two constant volume

18. What will be the volume of air at 327°C if its volume at 27°C is 1.5 m3/mt
3 m3/mt	1.5 m3/mt
18 m3/mt	6 m3/mt

19. The work done per unit mass of air in compression will'be least when n is equal to _____.
1	1.2
1.3	1.4

20. Isothermal compression though most efficient, but is not -practicable because
ityrequires very big cylinder	it does not increase pressure much
it is impossible in practice	compressor has to run at very slow speed to achieve it