Explore topic-wise MCQs in Mechanical Engineering.

This section includes 70 Mcqs, each offering curated multiple-choice questions to sharpen your Mechanical Engineering knowledge and support exam preparation. Choose a topic below to get started.

51.

In a centrifugal compressor, the flow of air is __________ to the axis of compressor.

A. parallel
B. perpendicular
C. inclined
D. none of these
Answer» C. inclined
52.

The workdone on a compressor will be minimum if air is taken from

A. the atmosphere
B. a source at 0° C
C. a source of low temperature air
D. a source of high temperature air
Answer» D. a source of high temperature air
53.

The compression ratio for the compressor is always __________ unity.

A. equal to
B. less than
C. more than
Answer» D.
54.

The assumption made in two stage compression with intercooler is that

A. there is no pressure drop in the intercooler
B. the compression in both the cylinders is polytropic
C. the suction and delivery of air takes place at constant pressure
D. all of the above
Answer» E.
55.

A simple turbo-jet engine is basically a gas turbine engine equipped with a propulsive nozzle and diffuser.

A. Agree
B. Disagree
Answer» B. Disagree
56.

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
Answer» D. six times
57.

For a multi-stage compressor, the polytropic efficiency is constant throughout for all the stages.

A. True
B. False
Answer» B. False
58.

The operation of the reciprocating air motor is similar to reciprocating air compressor.

A. True
B. False
Answer» C.
59.

Standard air is the air at __________ and relative humidity of 36 percent.

A. 0.1 bar and 20° C
B. 1 bar and 20° C
C. 0.1 bar and 40° C
D. 1 bar and 40° C
Answer» C. 0.1 bar and 40° C
60.

The volumetric efficiency of the compressor is defined as the ratio of volume of free air delivery per stroke to the swept volume of the piston.

A. Yes
B. No
Answer» B. No
61.

A compressor must be driven by some prime mover.

A. Agree
B. Disagree
Answer» B. Disagree
62.

Volumetric efficiency of a compressor decreases with __________ in compression ratio.

A. decrease
B. increase
Answer» C.
63.

Slip factor in a centrifugal compressor indicates the amount of air leaked from the storage vessel.

A. Yes
B. No
Answer» C.
64.

A turbo-prop is preferred to turbo-jet because

A. it has high propulsive efficiency at high speeds
B. it can fly at super sonic speeds
C. it can fly at high elevations
D. it has high power for take off
Answer» E.
65.

The speed of rotary air compressor is __________ as compared to reciprocating air compressor.

A. high
B. low
Answer» B. low
66.

The basic principle of the rocket propulsion is the same as that of jet propulsion.

A. Yes
B. No
Answer» B. No
67.

The overall thermal efficiency of an ideal gas turbine plant is (where = Pressure ratio)

A. 1 -
Answer» D.
68.

A centrifugal compressor is an axial flow compressor.

A. Correct
B. Incorrect
Answer» C.
69.

The ratio of the isentropic work to the Euler's work is known as pressure coefficient.

A. Yes
B. No
Answer» B. No
70.

The degree of reaction is usually kept __________ for all types of axial flow compressors.

A. 0.2
B. 0.3
C. 0.4
D. 0.5
Answer» E.