As Academictask believes that practice is the most important way to success so do visit www.academictask.com regularly and Brush up these Mechanical Engineering MCQs regularly to prepare for competitive & entrance exams like NTS, FPSC, ETEA, PPSC, KPPSC, etc. Prepare yourself for government job exams, interviews, and make your career in engineering. Aspiring students and professionals can learn and practice our Mechanical Engineering material MCQs. Here you will find questions & answers with detailed explanations. Mechanical Engineering Objective Questions and answer cover the topic like Engineering Materials, Fluid Mechanics, Hydraulic Machines, Machine Design, Engineering Mechanics, Nuclear Power Plants, Steam Boilers, Engines, Nozzles, Turbines, Compressors, Gas Turbines, Jet Engines, Thermodynamics, Engineering Metrology, Heat Transfer, etc. Also, check basic Electrical engineering MCQs here.

41. 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
E. 1.5

42. An ideal air compressor cycle with 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
E. two isobaric, two adiabatic and one constant volume

43. Compression efficiency is compared against_____________________?

A. ideal compression
B. adiabatic compression
C. botii isothermal and adiabatic compression
D. isentropic compression
E. isothermal compression

44. Aeroplanes employ following type of compressor_______________?

A. radial flow
B. axial flow
C. centrifugal
D. combination of above
E. none of the above

45. Ratio of indicated H.P. and brake H.P. is known as________________?

A. mechanical efficiency
B. volumetric efficiency
C. isothermal efficiency
D. adiabatic efficiency
E. relative efficiency

46. 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
E. none of the above

47. Volumetric efficiency of air compressors is of the order of________________?

A. 20-30%
B. 40-50%
C. 60-70%
D. 70-90%
E. 90-100%

48. Volumetric efficiency of a compressor without clearance volume________________?

A. increases with increase in compression ratio
B. decreases with increase in compression ratio
C. is not dependent upon compressin ratio
D. may increase/decrease depending on compressor capacity
E. unpredictable

49. 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
E. proportional to compression ratio

50. Ratio of compression is the ratio of__________________?

A. gauge discharge pressure to the gauge intake pressure
B. absolute discharge pressure to the ab-solute intake pressure
C. pressures at discharge and suction cor-responding to same temperature
D. stroke volume and clearance volume
E. none of the above

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