hydraulic machines Mcqs
51. In a single casing, multistage pump running at constant speed, the capacity rating is to be slightly lowered. It can be done by_______________?
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A. trimming the impeller size to the required size by machining

B. designing new impeller

C. none of the above

D. not possible

E. some other alterations in the impeller

52. For starting an axial flow pump, its delivery valve should be____________________?
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A. closed

B. partly open and partly closed

C. depends on starting condition and flow desired

D. could be either open or closed

E. open
53. The flow rate in gear pump___________________?
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A. none of the above

B. decreases with increase in pressure

C. unpredictable

D. increases with increase in pressure

E. more or less remains constant with in-crease in pressure
54. Medium specific speed of a pump implies it is_________________?
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A. axial flow pump

B. any one of the above

C. mixed flow pump

D. centrifugal pump

E. none of the above

55. The horse power required in above case will be___________________?
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A. 0.75 B.H.P.

B. B.H.P./0.75

C. 1.5 B.H.P.

D. same

E. none of the above

56. Saving of work done and power by fitting an air vessel to single acting reciprocating pump is of the order of__________________?
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A. 39.20%

B. 49.20%

C. 84.8%

D. 91.6%.

E. 68.80%

57. Hydraulic accumulator is used for____________________?
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A. accumulating hydraulic energy

B. supplying energy when main supply fails

C. accumulating oil

D. generally high pressures to operate hydraulic machines

E. supplying large quantities of oil for very short duration

58. Runaway speed of a hydraulic turbine is_________________?
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A. the speed corresponding to maximum overload permissible

B. the speed at which turbine runner will be damaged

C. none of the above.

D. full load speed

E. the speed if the turbine runner is allowed to revolve freely without load and with the wicket gates wide open
59. Francis, Kaplan and propeller turbines fall under the category of___________________?
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A. Reaction-cum-impulse turbines

B. Mixed flow turbines

C. Reaction turbines

D. Impulse turbines

E. Axial flow turbines

60. In a centrifugal pump, the liquid enters the pump__________________?
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A. at the top

B. at the bottom

C. at the center

D. none of the above

E. from sides

61. According to fan laws, for fans having constant wheel diameter, the pressure varies________________?
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A. square root of fan speed

B. directly as fan speed

C. square of fan speed

D. none of the above

E. cube of fan speed

62. The specific speed of turbine is defined as the speed of a unit___________________?
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A. of such a size that it delivers unit dis-charge at unit power

B. of such a size that it produces unit horse power with unit head

C. none of the above

D. of such a size that it requires unit power per unit head

E. of such a size that it delivers unit dis-charge at unit head