3. The runaway speed of a hydraulic turbine is the speed
Correct : D. at which the turbine will run freely without load
4. In an impulse turbine, the jet of water impinges on the bucket with a low velocity and after flowing over the vanes, leaves with a high velocity.
Correct : B. False
5. The gross or total head of the turbine is the
Correct : B. difference
6. The specific speed of a centrifugal pump, delivering 750 litres of water per second against a head of 15 metres at 725 r.p.m., is
Correct : C. 82.4 r.p.m.
7. In a reciprocating pump, air vessels are used to
Correct : D. reduce acceleration head
8. The capacity of a hydraulic accomulator is generally specified as the maximum amount of energy stored.
Correct : A. True
9. A Pelton wheel develops 1750 kW under a head of 100 metres while running at 200 r.p.m. and discharging 2500 litres of water per second. The unit power of the wheel is
Correct : C. 1.75 kW
10. In a reaction turbine, the pressure head of water, while flowing over the vanes, is converted into kinetic head before leaving the wheel.
Correct : B. Disagree
11. A turbine is required to develop 1500 kW at 300 r.p.m. under a head of 150 m. Which of the following turbine should be used?
Correct : A. Pelton wheel with one nozzle
12. A Kaplan turbine is an axial flow reaction turbine.
Correct : A. Correct
13. The action of a centrifugal pump is that of a reversed reaction turbine.
Correct : A. Correct
14. Geometric similarity is said to exist between the model and the prototype, if both of them
Correct : C. are identical in shape, but differ only in size
15. A Pelton wheel working under a constant head and discharge, has maximum efficiency when the speed ratio is
Correct : C. 0.46
16. Delivery head of water of a centrifugal pump is inversely proportional to diameter of its impeller.
Correct : B. No
17. The efficiency of a reaction turbine for a given head
Correct : A. decreases
18. The undershot water wheels are those in which
Correct : B. the wheel runs entirely by the impulse of water
19. In the casing of a centrifugal pump, the kinetic energy of the water is converted into pressure energy before the water leaves the casing.
Correct : A. True
20. Head developed by a centrifugal pump is
Correct : C. proportional to diameter and speed of impeller
21. The ratio of quantity of liquid discharged per second from the pump to the quantity of liquid passing per second through the impeller is known as
Correct : D. volumetric efficiency
22. The efficiency of a Pelton wheel working under constant head
Correct : B. increases
23. The cavitation in ahydraulic machine
Correct : D. all of the above
24. The principle of jet propulsion is used in driving the ships and aeroplanes.
Correct : A. Correct
25. Which of the following statement is correct as regard to water wheels?
Correct : D. all of the above
26. If the ratio of corresponding velocities at corresponding points are equal, then the model and the prototype are said to have dynamic similarity.
Correct : B. Wrong
27. Dynamic similarity is said to exist between the model and the prototype, if both of them
Correct : D. none of the above
28. The speed of an imaginary turbine, identical with the fiven turbine, which will develop a unit power under a unit head, is known as
Correct : C. specific speed
29. Which of the following pump is sucessfully used for lifting water to the wells?
Correct : D. Air-lift pump
30. Which of the following pump is preferred for flood control and irrigation applications?
Correct : B. Axial flow pump
31. In a centrifugal pump, the regulating valve is provided on the
Correct : B. delivery pipe
32. In a reciprocating pump, air vessels are fitted to the suction pipe and deliver pipe close to the cylinder of the pump.
Correct : A. True
33. For 450 m head of water,
Correct : A. Pelton wheel
34. Delivery head of a centrifugal pump is
Correct : C. directly proportional to N2
35. The discharge through a turbine is
Correct : A. directly proportional to H1/2
36. The flow ratio of Francis turbine is defined as the ratio of the
Correct : A. velocity of flow at inlet to the theoretical jet velocity
37. A Kaplan turbine is preferred for a specific speed of 300 to 1000 r.p.m.
Correct : A. Yes
38. Which of the following is not a reaction turbine?
Correct : D. Pelton wheel
39. A hydraulic ram is a device used to
Correct : D. to lift small quantity of water to a greater height when a large quantity of water is available at a smaller height
40. In a mixed flow centrifugal pump, the flow through the impeller is a combination of radial and axial flows.
Correct : A. Correct
41. In an impulse turbine, the pressure of water both at entering and leaving the vanes, is atmospheric.
Correct : A. Agree
42. Which of the following pump is suitable for small discharge and high heads?
Correct : D. Reciprocating pump
43. In a Kaplan turbine runner, the number of blades are generally between
Correct : B. 4 to 8
44. A turbine develops 10000 kW under a head of 25 metres at 135 r.p.m. Its specific speed is
Correct : C. 241.5 r.p.m.
45. Which of the following trubine is preferred for 0 to 25 m head of water?
Correct : B. Kaplan turbine
46. The overshot water wheels are those in which the wheel runs entirely by the
Correct : A. weight
47. In order to avoid cavitation in centrifugal pumps
Correct : A. the suction pressure should be high
48. Manometric head, in case of a centrifugal pump, is equal to
Correct : D. all of the above
49. A hydraulic coupling belongs to the category of
Correct : C. energy transfer machines
50. Overall efficiency of a centrifugal pump is the ratio of
Correct : B. actual workdone by the pump to the energy supplied to the pump by the prime mover
51. A hydraulic press is a device used
Correct : C. to lift larger load by the application of a comparatively much smaller force
52. Power required to drive a centrifugal pump is
Correct : A. directly
53. Slip of a reciprocating pump is defined as the
Correct : C. difference of theoretical discharge and the actual discharge
54. Work done by a turbine
Correct : A. depends
55. The type of centrifugal pump preferred for a specific speed of 20 r.p.m. is
Correct : A. slow speed pump with radial flow at outlet
56. Power required to drive a centrifugal pump is directly proportional to
Correct : D. fourth power of diameter
57. The cavitation in a hydraulic machine is mainly due to
Correct : C. low pressure
58. The overall efficiency of a reaction turbine is the ratio of
Correct : A. power produced by the turbine to the energy actually suppied by the turbine
59. A Francis turbine is used when the available head of water is
Correct : B. 25 m to 250 m
60. The cavitation in reaction turbines is avoided, to a great extent by
Correct : D. all of the above
61. A hydraulic intensifier is a device used to increase the intensity of pressure of water by means of energy available from a large quantity of water at a low pressure.
Correct : A. Right
62. In a reaction turbine, the water enters the wheel under pressure and flows over the vanes.
Correct : A. Correct
63. The efficiency of jet propulsion for a ship with inlet orifices at right angles to the direction of motion of ship, will be maximum when the relative velocity of the jet and ship is equal to twice the velocity of the ship.
Correct : A. Yes
64. In the above question, the unit speed of the wheel is
Correct : B. 20 r.p.m.
65. The specific speed of a centrifugal pump may be defined as the speed of an imaginary pump, identical with the given pump, which will discharge one litre of water, while it is being raised through a head of one metre.
Correct : A. True
66. In a centrifugal pump, the water enters the impeller
Correct : B. radially
67. In the above question, the saving in case of a double acting reciprocating pump is
Correct : A. 39.20%
68. The specific speed from 160 to 500 r.p.m. of a centrifugal pump indicates that the pump is
Correct : D. high speed with axial flow at outlet
69. The hydraulic efficiency of a reaction turbine, is the ratio of
Correct : C. workdone on the wheel to the energy (or head of water) actually supplied to the turbine
70. Kinematic similarity is said to exist between the model and the prototype, if both of them
Correct : A. have identical velocities
71. By fitting an air vessel to the reciprocating pump, there is always a saving of work done and subsequently saving of power. This saving in case of a single acting reciprocating pump is
Correct : C. 84.80%
72. The discharge through a reaction turbine
Correct : C. decreases
73. The power produced by the reaction turbine is
Correct : A. directly proportional
74. A hydraulic accumulator is a device used to store
Correct : B. pressure
75. Braking jet in an impulse turbine is used
Correct : B. to bring the runner to rest in a short time
76. Mechanical efficiency of a centrifugal pump is the ratio of
Correct : A. energy available at the impeller to the energy supplied to the pump by the prime mover
77. The impeller of a centrifugal pump may have
Correct : D. any one of these
78. In a mixed flow reaction turbine, the flow of water is partly radial and partly axial.
Correct : A. Correct
79. The efficiency of a centrifugal pump will be maximum when the blades are bent backward.
Correct : A. Yes
80. The specific speed of a hydraulic turbine depends upon
Correct : D. speed, power developed and head of water
81. The speed ratio of a Francis turbine is defined as the ratio of the theoretical jet velocity to the peripheral speed at inlet.
Correct : B. No
82. A jet of water is striking at the centre of a curved vane moving with a uniform velocity in the direction of jet. For the maximum efficiency, the vane velocity is
Correct : B. one-third
83. Slip of a reciprocating pump is negative, when
Correct : D. suction pipe is long and delivery pipe is short and the pump is running at high speeds
84. The overall efficiency for a Pelton wheel lies between
Correct : D. 0.85 to 0.90
85. Which of the following statement is wrong?
Correct : D. A Francis turbine is an impulse turbine.
86. In a reaction turbine, the draft tube is used
Correct : C. to increase the head of water by an amount equal to the height of the runner outlet above the tail race
87. For centrifugal pump impeller, the maximum value of the vane exit angle is
Correct : C. 20? to 25?
88. When the speed of the pump increases, its net positive suction head (NPSH) requirement decreases.
Correct : B. Disagree
89. Which of the following is not an impulse turbine?
Correct : D. Kaplan turbine
90. In an axial flow reaction turbine, the water flows
Correct : A. parallel
91. The depth of the bucket for a Pelton wheel is generally
Correct : B. 1.2 times
92. The width of the bucket for a Pelton wheel is generally
Correct : D. five times
93. The speed of a turbine runner is
Correct : A. directly proportional to H1/2
94. The hydraulic efficiency of an impulse turbine is the
Correct : C. ratio of the work done on the wheel to the energy of the jet
95. Which of the following pump is generally used to pump highly viscous fluid?
Correct : D. Screw pump
96. An impulse turbine is used for
Correct : B. high head of water
97. In an inward flow reaction turbine
Correct : C. the water enters the wheel at the outer periphery and then flows towards the centre of the wheel
98. The specific speed of a turbine is the speed of an imaginary turbine, identical with the given turbine, which
Correct : C. develops unit power under unit head
99. The jet ratio is defined as the ratio of the
Correct : C. diameter of Pelton wheel to the diameter of jet