chemical engineering fluid mechanics for chemical chemical engineering Mcqs
51. The ratio of pressure forces to inertial forces is called the _______________ number?
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A. Euler

B. Froude

C. Mach

D. Reynold

52. Pressure drop in packed bed for turbulent flow is given by the ______________ equation?
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A. Levas

B. Blake-Plummer

C. Kozeny-Carman

D. Hagen-Poiseuilles

53. Function of air vessel provided in a reciprocating pump is to_________________?
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A. Reduce discharge fluctuation

B. Avoid the necessity of priming

C. Increase the pump efficiency

D. Reduce the danger of cavitation

54. Purpose of air lift pump is to____________________?
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A. Lift compressed air

B. Lift water from a well by using compressed air

C. Compress air

D. Lift air under negative pressure

55. What is the shear rate at the pipe wall, in case of laminar flow of Newtonian fluids in a pipe of diameter D & length L incurring a pressure drop ?p with average velocity Vavg ?
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A. D ?p/8L

B. 8 Vavg/D

C. D ?p/4L

D. 4 Vavg/D

56. Equivalent length of a pipe fitting is____________________?
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A. None of these

B. Dependent on Reynolds number

C. Independent of Reynolds number

D. Dependent on the length of the pipe

57. A hydraulic accumulator comprises of__________________?
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A. A cylinder and a plunger

B. A storage device and a control valve

C. Two pistons and two cylinders

D. A storage tank and a ram pump

58. In magnetic flow meters, voltage generation is________________?
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A. Due to the motion of conducting fluid through an externally generated uniform field

B. Proportional to the fluid velocity

C. Both A. and B.

D. Neither A. nor B.

59. Select the correct practical example of steady non-uniform flow?
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A. Steadily decreasing flow through a reducing section

B. Steadily increasing flow through a pipe

C. Motion of river around bridge piers

D. Motion of water around a ship in a lake

60. Foot valves are provided in the suction line of a centrifugal pump to ____________________?
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A. Minimise the fluctuation in discharge

B. Avoid priming, every time we start the pump

C. Remove the contaminant present in the liquid

D. Control the liquid discharge

61. In a/an _____________, the flow rate of fluids is obtained by measuring the difference between the impact and the static pressure?
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A. Rotameter

B. Pitot tube

C. Flow nozzle

D. Venturimeter

62. Actual lift of a pump is always less than the theoretical lift and is limited by the__________________________?
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A. Specific gravity & temperature of the liquid

B. Frictional resistance through pipes, fittings & passages

C. All A., B. and C.

D. Leakage & pressure decreasing at higher elevations

63. Fanning friction factor equation applies to the _____________ fluid flow?
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A. Non-isothermal condition of

B. Compressible

C. Both A. and B.

D. Neither A. nor B.
64. The equation relating friction factor to Reynold number, f-0.5 = 4 loge (NRe/?f)-0.4, is called the _____________ equation?
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A. Nikuradse

B. Colebrook

C. Von-Karman

D. Blasius

65. For a fluid rotating at constant angular velocity about vertical axis as a rigid body, the pressure intensity varies as the___________________?
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A. Radial distance linearly

B. Inverse of the radial distance

C. Elevation along vertical direction

D. Square of the radial distance
66. With the increase in depth, the hydrostatic pressure in an un-accelerated incompressible fluid (in a constant gravitational field) ?
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A. Increases exponentially

B. Decreases

C. Increases linearly

D. Remain constant

67. In case of turbulent flow of fluid through a circular pipe, the __________________?
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A. Velocity profile becomes flatter and flatter with increasing Reynolds number

B. Point of maximum instability exists at a distance of 2r/3 from the pipe wall (r = pipe radius)

C. file at the wall are more</strong>

D. Mean flow velocity is about 0.5 times the maximum velocity

E. Skin friction drag, shear stresses, random orientation of fluid particles and slope of velocity
68. Which of the following relationship is valid for the equilibrium position of the float in a Rotameter? (Where, Df= Drag force on the float Bf = Buoyant force on the float Wf = Weight of the float)?
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A. Df + Bf + Wf =0

B. Df + Bf = Wf

C. None of these

D. Df = Bf + Wf

69. A centrifugal pump has the following specifications: Power = 4 H.P.; Speed = 800 rpm Head = 8 metres Flow = 1000 litres/minutes. If its speed is halved, the new discharge will be __________ litres/minute ?
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A. 750

B. 1000

C. 500

D. 200

70. For steady ideal fluid flow, the Bernoullis equation states that the_________________?
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A. Energy is constant throughout the fluid

B. Velocity is constant along a stream line

C. None of these

D. Energy is constant along a stream line, but may vary across stream lines
71. Glass pipes can be joined by__________________?
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A. Soldering

B. Flanges

C. Bell and spigot joint

D. Welding

72. An isentropic process is the one, in which_________________?
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A. pvr= constant

B. pvr = constant, and process is reversible

C. None of these

D. pv = constant

73. Horsepower increase of a centrifugal gas compressor without altering the volumetric flow rate will _____________ the gas discharge pressure?
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A. Decrease

B. Increase

C. Exponentially decrease

D. Not change

74. For the same terminal conditions and fitting size, the least friction loss is incurred in a/an ?
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A. Union

B. T-joint

C. 45 elbow

D. 90bend

75. What type of motion the fluid element undergoes, when it changes from one position to another position, such that the angle between the two sides changes ?
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A. Linear deformation

B. Angular deformation

C. Rotation

D. Translation

76. The ______________ pressure is measured by a static tube?
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A. Total

B. Static

C. Dynamic

D. None of these

77. The ratio of inertial forces to viscous forces is called the ______________ number?
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A. Mach

B. Weber

C. Reynold

D. Froude

78. In parallel pipe problems, the__________________?
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A. Discharge is the same through all the pipes

B. Head loss is the same through each pipe

C. None of these

D. Total head loss is equal to the sum of the head losses through each pipe

79. A centrifugal pump used to pump water is used to pump an oil with specific gravity of 0.8 at the same rate. The power consumption will now_________________?
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A. Increase

B. Decrease

C. Remain same

D. Data insufficient to predict

80. The maximum discharge through a circular channel takes place, when the depth of the fluid flow is ______________ times the pipe diameter?
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A. 0.5

B. 0.25

C. 0.66

D. 0.95
81. Lower BWG means _____________ of the tube?
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A. Lower thickness

B. Inner diameter

C. Outer diameter

D. Lower cross-section
82. Which of the following is most prone to pulsating discharge flow ?
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A. Reciprocating pump

B. Gear pump

C. Axial flow pump

D. Centrifugal pump

83. If two capillary tubes of dia 0.5 mm and 1 mm are dipped in a pot containing mercury, then the rise of mercury is_________________?
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A. Same in both the tubes

B. Greater in 1 mm dia tube

C. Greater in 0.5 mm dia tube

D. Zero in both the tubes

84. Which of the following is not a dimension-less parameter ?
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A. Kinematic viscosity

B. Pressure-co-efficient

C. Weber number

D. Froude number

85. Purpose of relief valve in a reciprocating pump is to___________________?
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A. Reduce the discharge pressure

B. Control the rate of discharge

C. Facilitate unidirectional flow of liquid

D. Protect the pump against developing excessive pressure
86. Velocity head on sudden enlargement in a horizontal pipe is converted into ______________ head?
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A. Elevation

B. Pressure

C. Both A. & B.

D. Neither A. nor B.

87. Slurries can be most conveniently pumped by a _______________ pump?
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A. Reciprocating

B. Screw

C. Centrifugal

D. Gear

88. Pressure drop for turbulent fluid flow through a circular pipe is given by_________________?
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A. 4f (L/D) (v2/2gc). ?

B. 32?LV/gc.D2

C. 64/Re

D. f (L/D) (v2/2gc). ?

89. For a given fluid flow rate, which of the following incurs maximum head loss ?
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A. All of them incur the same head loss

B. Orificemeter

C. Flow nozzle

D. Venturimeter

90. Transition length for turbulent flow in smooth pipe is equal to _____________ times the pipe diameter?
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A. 500

B. 0.5

C. 50

D. 5

91. The energy loss over a length of pipeline according to Darcy-Weisbach equation for pipe flow is _______________ the mean velocity of flow?
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A. Directly proportional to

B. Inversely proportional to square of

C. Inversely proportional to

D. Directly proportional to square of
92. Pressure drop in a fluidised bed reactor is ______________ that in a similar packed bed reactor?
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A. Less than

B. None of these

C. Same as

D. Greater than
93. In case of a pipe exit fitted with a nozzle, the____________________?
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A. Conversion of kinetic head to pressure head is facilitated

B. Conversion of pressure head to kinetic head is facilitated

C. Power transmitted through the nozzle is maximum, when the head lost due to friction in the

D. e is equal to one third of the total supply head

E. Both B. and C.
94. Prandtl mixing length is___________________?
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A. Applicable to laminar flow problems

B. Zero at the pipe wall

C. A universal constant

D. None of these

95. A Pitot tube indicates 5 cm of water (manometer) when it is being used for measuring velocity of air. The velocity of air in m/sec is___________________?
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A. 14.1

B. 28.2

C. 56.22

D. 5

96. The continuity equation of fluid mechanics utilises the principle of conservation of _________________?
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A. Momentum

B. Mass

C. Energy

D. Both B. & C.

97. Discharge in laminar flow through a pipe varies________________?
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A. As the square of the diameter

B. As the square of the radius

C. Inversely as the viscosity

D. Inversely as the pressure drop

98. Power required by a centrifugal pump is proportional to (where, D = diameter, N = r.p.m) ________________?
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A. N3D5

B. N2D

C. N2D3

D. ND2

99. Forces acting on a particle settling in fluid are _____________ forces?
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A. Gravitational & buoyant

B. Centrifugal & drag

C. External, drag & viscous

D. Gravitational or centrifugal buoyant drag
100. Fanning friction factor for laminar flow of fluid in a circular pipe is____________________?
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A. Not a function of the roughness of pipe wall

B. Inversely proportional to Reynolds number

C. Both A. & B.

D. Neither A. nor B.