Top 50+ Solved Air Compressors MCQ Questions Answer
Q. What is the correct formula for net work done of reciprocating engine?
a. Wnet = mean effective pressure × clearance volume
b. Wnet = mean effective pressure × total volume of cylinder
c. Wnet = mean effective pressure × displacement volume
d. none of the above
Q. Minimum work in compressor is possible when the value of adiabatic index n is equal to
a. 0.75
b. 1
c. 1.27
d. 1.35
Q. Compressed air coming out from a punctured football
a. becomes hotter
b. becomes cooler
c. remains at the same temperature
d. may become hotter or cooler depending upon the humidity of the surrounding air
Q. The capacity of a compressor is 5 m /min. 5 m /min refers to
a. standard air
b. free air
c. compressed air
d. compressed air at delivery pressure
Q. The overall isothermal efficiency of compressor is defined as the ratio of
a. isothermal h.p. to the BHP of motor
b. isothermal h.p. to adiabatic h.p.
c. power to drive compressor to isothermal h.p.
d. work to compress air isothermally to work for actual compression
Q. The- most efficient method of compressing air is to compress it
a. isothermally
b. adiabatically
c. isentropically
d. isochronically
Q. Maximum work is done in compressing air when the compression is
a. isothermal
b. adiabatic
c. polytropic
d. any one of the above
Q. The pressure and temperature conditions of air at the suction of compressor are
a. pressure sightly less than atmospheric and temperature slightly more than atmospheric.
b. slightly more than atmospheric
c. slightly less than atmospheric
d. pressure slightly more than atmospheric and temperature slightly less than atmospheric
Q. Isothermal compression effeicency can be attained by running the compressor
a. at very high speed
b. at very slow speed
c. at average speed
d. at zero speed
Q. The compressor capacity with decrease in suction temperature
a. increases
b. decreases
c. remains unaffected
d. may increase or decrease depending on compressor capacity
Q. Isothermal compression efficiency, even when running at high speed, can be approached by using
a. multi-stage compression
b. cold water spray
c. both (a) and (b) above
d. fully insulating the cylinder
Q. Compression efficiency is compared against
a. ideal compression
b. adiabatic compression
c. isothermal compression
d. isentropic compression
Q. Aeroplanes employ following type of compressor
a. radial flow
b. axial flow
c. centrifugal
d. combination of above
Q. Inter cooling in compressors
a. cools the delivered air
b. results in saving of power in compressing a given volume to given pressure
c. is the standard practice for big compressors
d. enables compression in two stages
Q. An ideal air compressor cycle without clearance on p-v diagram can be represented by following processes
a. one adiabatic, two isobaric, and one constant volume
b. two adiabatic and two isobaric
c. two adiabatic, one isobaric and one constant volume
d. one adiabatic, one isobaric and two constant volume