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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. | |