mechanical engineering MCQs – Page 206

Practise multiple-choice questions from mechanical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

4101. In axial flow fans and turbines, fluid enters and leaves as follows________________?
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A. axially, axially

B. axially, radially

C. combination of axial and radial

D. radially, radially

E. radially, axially

4102. In reaction turbine, draft tube is used_____________________?
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A. none of the above

B. to transport water downstream without eddies

C. to increase flow rate

D. for safety of turbine

E. to convert the kinetic energy to flow energy by a gradual expansion of the flow cross-section
4103. Reciprocating pumps are no more to be seen in industrial applications (in comparison to centrifugal pumps) because of____________________?
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A. necessity of air vessel

B. all of the above

C. lower discharge

D. lower speed of operation

E. high initial and maintenance cost
4104. In a centrifugal pump casing, the flow of water leaving the impeller, is___________________?
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A. forced vortex

B. free vortex motion

C. none of the above

D. rectilinear flow

E. radial flow

4105. In centrifugal pumps, maximum efficiency is obtained when the blades are_________________?
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A. straight

B. bent forward

C. radial

D. given aerofoil section

E. bent backward
4106. High specific speed of turbine implies it is__________________?
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A. any one of the above

B. impulse turbine

C. Francis turbine

D. propeller turbine

E. none of the above

4107. Axial flow pump is started with its delivery valve________________?
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A. none of the above

B. kept 50% open

C. irrespective of any position

D. kept fully open

E. kept fully closed

4108. Pressure intensifier increases the pressure in proportion to____________________?
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A. fourth power of ratio of diameters

B. ratio of diameters

C. inverse ratio of diameters

D. square of inverse ratio of diameters

E. square of ratio of diameters
4109. For small discharge at high pressure, following pump is preferred_____________________?
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A. reciprocating

B. mixed flow

C. centrifugal

D. propeller

E. axial flow

4111. High specific speed of a pump implies it is_____________________?
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A. centrifugal pump

B. any one of the above

C. axial flow pump

D. mixed flow pump

E. none of the above

4112. Multistage centrifugal pumps are used to obtain___________________?
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A. pumping of viscous fluids

B. high head

C. high discharge

D. high head and high discharge

E. high efficiency

4113. Indicator diagram of a reciprocating pump is a graph between________________?
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A. flow vs swept volume

B. pressure in cylinder vs swept volume

C. swept volume vs speed

D. flow vs speed

E. pressure vs speed

4115. Puck up the wrong statement about centrifugal pump_______________?
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A. Power a speed3

B. none of the above is wrong

C. head a speed2

D. discharge a diameter

E. head a diameter

4116. According to fan laws, at constant weight of air or gas, the speed, capacity and pressure vary________________?
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A. as square root of density

B. as square of density

C. directly as the air or gas density

D. inversely as square root of density

E. inversely as density
4117. Which place in hydraulic turbine is most susceptible for cavitation __________________?
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A. draft tube exit

B. penstock

C. inlet of draft rube

D. blade inlet

E. guide blade

4118. According to fan laws, for the fans having constant wheel diameters, the power demand varies_______________?
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A. square root of fan speed

B. directly as fan speed

C. none of the above

D. cube of fan speed

E. square of fan speed

4119. Maximum impulse will be developed in hydraulic ram when ___________________?
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A. waste valve closes suddenly

B. supply pipe is long

C. supply pipe has critical diameter

D. ram chamber is large

E. supply pipe is short

4120. Centrifugal pump is started with its delivery valve __________________?
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A. kept fully closed

B. kept 50% open

C. kept fully open

D. irrespective of any position

E. none of the above