M C Q s D r i v e

Mechanical Engineering Mcqs 1919 MCQs [All-Courses]

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Mechanical Engineering MCQs prepared for job test and interview preparation, especially for fresh graduates, students, and candidates appearing in competitive exams. These multiple-choice questions cover key topics such as Machine Design, Theory of Machines, Hydraulic Machines, and other important mechanical engineering concepts.

For minimum work in multistage compression, assuming same index of compression in all stages_________________?
A work done in first stage should be more
B work done in subsequent stages should increase
C work done in subsequent stages should decrease
D work done in all stages should be equal
Correct Answer: work done in all stages should be equal
For supplying intermittent small quantity of air at high pressure, following compressor is best suited__________________?
A centrifugal
B reciprocating
C axial
D screw
Correct Answer: reciprocating
Diffuser in a compressor is used to _____________________?
A increase velocity
B make the flow stream-line
C convert pressure energy into kinetic energy
D convert kinetic energy into pressure energy
Correct Answer: convert kinetic energy into pressure energy
Phenomenon of choking in compressor means __________________?
A no flow of air
B fixed mass flow rate regardless of pressure ratio
C reducing mass flow rate with increase in pressure ratio
D increased inclination of chord with air steam
Correct Answer: fixed mass flow rate regardless of pressure ratio
The ratio of isentropic work to Euler work is known as_____________________?
A pressure coefficient
B work coefficient
C polytropic reaction
D slip factor
Correct Answer: pressure coefficient
The indicated work per unit mass of air delivered is___________________?
A directly proportional to clearance volume
B greatly affected by clearance volume
C not affected by clearance volume
D inversely proportional to clearance volume
Correct Answer: not affected by clearance volume
As the value of index ‘«’ is decreased, the volumetric efficiency will___________________?
A increase
B decrease
C remain unaffected
D may increase/decrease depending on compressor clearance
Correct Answer: decrease
In a compressor, free air delivered is the actual volume delivered at the stated pressure reduced to ____________________?
A N.T.P. conditions
B intake temperature and pressure conditions
C 0°C and 1 kg/cm2
D 20°C and 1 kg/cm2
Correct Answer: intake temperature and pressure conditions
The volumetric efficiency of a compressor falls roughly as follows for every 100 m increase in elevation___________________?
A 0.1%
B 0.5%
C 1.0%
D 5%
Correct Answer: 1.0%
During base load operation, the best method of controlling compressor is ___________________?
A start-stop motor
B constant speed unloader
C relief valve
D variable speed
Correct Answer: start-stop motor