fluid mechanics MCQs – Page 4

Practise focused fluid mechanics questions with marked answers for exam preparation and subject revision.

fluid mechanics Mcqs
61. The losses are more in_________________?
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A. critical flow

B. turbulent flow

C. transition flow

D. laminar flow

62. Select the incorrect statement?
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A. Coefficient of contraction is always less than one

B. Stream lines are parallel throughout the jet at vena contracta

C. The pressure intensity at vena contracta is atmospheric

D. Contraction is least at vena contracta

63. The correct relationship among displacement thickness d, momentum thickness m and energy thickness e is_________________?
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A. d > m > e

B. d > e > m

C. e > d > m

D. e > m > d

64. The discharge of a liquid of kinematic viscosity 4 cm2/sec through a 8 cm dia-meter pipe is 3200n cm7sec. The type of flow expected is__________________?
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A. not predictable from the given data

B. laminar flow

C. transition flow

D. turbulent flow

65. Centre of buoyancy always_________________?
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A. coincides with the centroid of the volume of fluid displaced

B. remains above the centre of gravity

C. coincides with the centre of gravity

D. remains below the centre of gravity

66. In case of an airfoil, the separation of flow occurs________________?
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A. any where between rear and front of body depending upon Reynolds number

B. at the extreme rear of body

C. at the extreme front of body

D. midway between rear and front of body

67. The horse power transmitted through a pipe is maximum when the ratio of loss of head due to friction and total head supplied is________________?
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A. 4-Jan

B. 3-Feb

C. 2-Jan

D. 1/3
68. Newtons law of viscosity relates________________?
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A. intensity of pressure and rate of angular deformation

B. shear stress and rate of angular deformation

C. viscosity and rate of angular deformation

D. shear stress, viscosity and temperature

69. The maximum thickness of boundary layer in a pipe of radius r is____________________?
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A. r/2

B. r

C. 0

D. 2r

70. The hydraulic grade line is_________________?
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A. always sloping downward in the direction of flow

B. never above the energy grade line

C. always above the centre line of pipe

D. all of the above

71. The point in the immersed body through which the resultant pressure of the liquid may be taken to act is known as__________________?
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A. center of gravity

B. metacentre

C. center of buoyancy

D. center of pressure
72. If a vessel containing liquid moves downward with a constant acceleration equal to g then_____________?
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A. there will be vacuum in the liquid

B. the pressure in the liquid mass is greater than hydrostatic pressure

C. the pressure throughout the liquid mass is atmospheric

D. none of the above

73. The major loss of energy in long pipes is due to_______________?
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A. sudden contraction

B. friction

C. gradual contraction or enlargement

D. sudden enlargement

74. A floating body is said to be in a state of stable equilibrium_________________?
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A. when the metacentre is below the centre of gravity

B. only when its centre of gravity is below its centre of buoyancy

C. when the metacentre is above the centre of gravity

D. when its metacentric height is zero

75. If a sphere of diameter 1 cm falls in castor oil of kinematic viscosity 10 stokes, with a terminal velocity of 1.5 cm/sec, the coefficient of drag on the sphere is________________?
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A. less than 1

B. 160

C. between 1 and 100

D. 200

76. Separation of flow occurs when_________________?
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A. the pressure intensity reaches a minimum

B. the cross-section of a channel is reduced

C. the boundary layer comes to rest

D. all of the above

77. In a Sutro weir, the discharge is proportional to________________?
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A. H

B. H3/2

C. H5/2

D. H1/2

78. For laminar flow in circular pipes, the Darcys friction factor f is equal to_________________?
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A. none of the above where R,, is Reynolds number

B. 64/ Re

C. 16/Re

D. 32/ Re

79. When the velocity distribution is uniform over the cross-section, the correction factor for momentum is__________________?
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A. 3-Apr

B. 1

C. 2

D. 0

80. Which of the following has highest coefficient of discharge ?
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A. venturimeter

B. sharp edged orifice

C. CipoUetti weir

D. Bordas mouthpiece running full