chemical engineering fluid mechanics for chemical chemical engineering Mcqs
101. The ratio of the depth of flow to the diameter of the channel for maximum discharge in a circular channel in open channel flow is________________?
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A. 1.85

B. 0.1

C. 0.55

D. 0.95
102. Drag co-efficient for flow past immersed body is the ratio of _____________ to the product of velocity head and density?
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A. Average drag per unit projected area

B. None of these

C. Shear stress

D. Shear force

103. I.D. of 1/4? schedule 40 pipe is 0.364?. I.D. of a 1/2? schedule 40 pipe would be ______________ inch?
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A. 0.474

B. 4.728

C. 0.622

D. 0.5

104. In a free vortex, the_____________________?
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A. Flow is necessarily rotational

B. Velocity changes linearly with radial distance

C. Radial component of velocity is same everywhere

D. Stream lines are not circular

105. Which of the following is the most common pump for pumping either raw sewage or sludge ?
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A. Electromagnetic pump

B. Reciprocating pump

C. Gear pump

D. Centrifugal pump

106. Poise is converted into stoke by ___________________?
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A. Dividing by density (gm/c.c)

B. Multiplying with specific gravity

C. Dividing by specific gravity

D. Multiplying with density (gm/c.c)

107. The fluid velocity varies as the square root of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop of _____________ fluid?
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A. Dilatent

B. Newtonian

C. Pseudo-plastic

D. Bingham plastic

108. Newtons law of viscosity relates the____________________?
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A. Pressure gradient and rate of angular deformation

B. Shear stress and velocity

C. Shear stress and rate of angular deformation in a fluid

D. Velocity gradient and pressure intensity

109. Toothpaste is a__________________?
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A. Dilatent

B. Pseudo-plastic

C. Newtonian liquid

D. Bingham plastic

110. Mach number is the ratio of the speed of the _____________________?
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A. Sound to that of the fluid

B. Light to that of the fluid

C. Fluid to that of the light

D. Fluid to that of the sound
111. In continuous fluidisation_________________?
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A. Velocity of the fluid is very small

B. Solids are completely entrained

C. There is no entrainment of solids

D. The pressure drop is less than that for batch fluidisation

112. Pressure drop (?p) for a fluid flowing in turbulent flow through a pipe is a function of velocity (V) as___________________?
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A. V2.7

B. V-0.2

C. V1.8

D. V2
113. The boundary layer thickness at a given section along a flat plate _____________ with increasing Reynolds number?
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A. Remain same

B. Increases

C. Decreases

D. May increase or decrease

114. A tube is specified by its____________________?
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A. Thickness & outer diameter both

B. Outer diameter only

C. Thickness only

D. Inner diameter

115. What is the ratio of displacement thickness to nominal thickness for a linear distribution of velocity in the boundary layer on a flat plate ?
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A. 1.5

B. 0.5

C. 1

D. 2

116. Fluid resistance to shear depends upon its_______________?
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A. Rate of transfer of molecular momentum

B. Cohesion

C. Both A. and B.

D. Neither A. nor B.

117. Transition length for a turbulent fluid entering into a pipe is around _____________ times the pipe diameter?
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A. 5

B. 50

C. 500

D. 5000

118. A piezometer provided in the pipe measures__________________?
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A. None of these

B. Static pressure

C. Friction factor

D. Dynamic pressure

119. A liquid is pumped at the rate of 600 litres using 1000 rpm. If the rpm is changed to 1100, the liquid pumped is _____________ litres?
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A. 660

B. 1.1

C. 60

D. 600

120. Bernoullis equation is not applicable, when the flow is___________________?
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A. Viscous

B. All A., B. & C.

C. Irrotational

D. Incompressible

121. Viscosity of water at 40C lies in the range of___________________?
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A. 1 10-3 to 2 10-3 kg/m.s

B. 0.5 to 1 kg/m.s

C. 0.5 10-3 to 1 10-3 kg/m.s

D. 1 to 2 kg/m.s

122. In deriving Bernoullis equation, fluid is assumed to be________________?
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A. Uniform, steady, incompressible, along a streamline

B. Steady, density being pressure dependent, frictionless

C. Incompressible, frictionless, steady, along a streamline

D. None of these

123. In a fluidised bed reactor___________________?
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A. Temperature gradients are very high

B. Segregation of the solids occurs

C. Hot spots are formed

D. Temperature is more or less uniform
124. Scale up of agitator design requires________________?
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A. Geometrical similarity only

B. Dynamic similarity only

C. Both geometrical and dynamic similarity

D. All geometrical, dynamic and kinematic similarity
125. The percentage slip in a reciprocating pump set is given by the % of (where, Q1 = actual discharge Q2 = theoretical discharge) ?
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A. (Q2 Q1)/Q1

B. Q2/Q1

C. (Q2 Q1)/Q2

D. Q1/Q2

126. In case of unsteady fluid flow, conditions & flow pattern change with the passage of time at a position in a flow situation. Which of the following is an example of unsteady flow ?
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A. Discharge of water by a centrifugal pump being run at a constant rpm

B. Water discharge from a vertical vessel in which constant level is maintained

C. Low velocity flow of a highly viscous liquid through a hydraulically smooth pipe

D. Water flow in the suction and discharge pipe of a reciprocating pump
127. For turbulent flow of an incompressible fluid through a pipe, the flow rate Q? is proportional to (? P)n, where ?P is the pressure drop. The value of exponent n is_________________?
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A. 0

B. < 1

C. 1

D. > 1

128. In Newtons law range, the drag co-efficient for the motion of spherical particle in a stationary fluid is___________________?
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A. 0.44

B. 4.4

C. 44

D. 0.044

129. In the complete turbulence zone (in rough pipes), the____________________?
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A. Rough and smooth pipes have the same friction factor

B. Laminar film covers the roughness projections

C. Friction factor is independent of the relative roughness

D. Friction factor depends upon NRe only

130. Potential flow is characterised by the___________________?
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A. Formation of eddies within the stream

B. One in which dissipation of mechanical energy into heat occurs

C. Irrotational and frictionless flow

D. Irrotational and frictional flow

131. Low specific speed of a pump implies that, it is a/an ______________ pump?
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A. Axial flow

B. Centrifugal

C. None of these

D. Mixed flow

132. A pressure of 10 m head of water is equivalent to ______________ kN/m2?
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A. 98

B. 147

C. 196

D. 49

133. The ratio of maximum to average velocity in case of streamline flow between parallel plates is______________________?
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A. 2.5

B. 1.5

C. 1

D. 2

134. A relief valve__________________?
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A. Unloads a pump

B. None of these

C. Provides back pressure for a cylinder

D. Is a directional control valve
135. In case of end to end connection of two or more pipes in series, the ______________ each pipe?
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A. Rate of flow in each pipe is proportional to the length of

B. Head loss is same through

C. Total flow rate is the sum of flow rate in

D. Same rate of flow passes through
136. Stokes equation is valid in the Reynolds number range__________________?
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A. 2 to 10

B. 0.1 to 2

C. 0.01 to 0.1

D. 10 to 100

137. Fluid flow through a packed bed is represented by the ______________ equation?
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A. Hagen-Poiseuilles

B. Fannings

C. None of these

D. Erguns
138. For laminar flow of a fluid through a packed bed of spheres of diameter d, the pressure drop per unit length of bed depends upon the sphere diameter as_________________?
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A. d2

B. d? 2

C. d4

D. d

139. Critical velocity in a pipe flow_________________?
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A. Increases as pipe diameter increases

B. Independent of fluid density

C. None of these

D. Increases as fluid viscosity increases

140. The vent valve provided in a liquid handling centrifugal pump is___________________?
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A. Generally a needle valve

B. Helpful in easy removal of samples

C. Used to release any gases that might be vapour locking the pump

D. All A., B. and C.
141. Discharge from a 24 inch pipe of water at 10 ft/sec will be _____________ ft3/sec?
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A. 32.36

B. 48.22

C. 125.6

D. 7.65

142. The fluid property, due to which, mercury does not wet the glass is__________________?
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A. Cohesion

B. Viscosity

C. Adhesion

D. Surface tension
143. The time of oscillation of a floating body is _________________?
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A. Dependent on the buoyant forces only

B. Independent of the Metacentric height

C. None of these

D. Longer, if Metacentric height is increased

144. The length of the tube necessary for the boundary layer to reach the centre of the tube and for fully developed flow to be established is called the _____________ length?
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A. None of these

B. Transition

C. Prandtl mixing

D. Equivalent

145. A Newtonian fluid is that__________________?
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A. For which shear & deformation are related as T = ? (?u/?y)

B. Which needs a minimum shear, before it starts deforming

C. Which follows Newtons law of motion

D. None of these

146. Velocity distribution for flow between two fixed parallel plates_________________?
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A. Is constant over the entire cross-section

B. Varies parabolically across the section

C. None of these

D. Is zero at the plates and increases linearly to the mid-plane

147. The fluid velocity varies as the cube of the cylindrical pipe diameter in case of steady state laminar flow at constant pressure drop for ____________ fluid?
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A. Dilatent

B. Newtonian

C. Bingham plastic

D. Pseudo-plastic
148. For the same flow rate of a fluid, the pressure drop is the least for ____________________?
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A. Flow-nozzle

B. ?p is same for all

C. Orificemeter

D. Venturimeter
149. A particle A of diameter 10 microns settles in an oil of specific gravity 0.9 and viscosity 10 poise under Stokes law. A particle B with diameter 20 microns settling in the same oil will have a settling velocity ?
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A. One fourth as that of A

B. Four times as that of A

C. Same as that of A

D. Twice as that of A

150. The drag co-efficient for a bacterium moving in water at 1 mm/s, will be of the following order of magnitude (assume size of the bacterium to be 1 micron and kinematic viscosity of water to be 10-6m2/s) ?
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A. 0.44

B. 0.24

C. 24000

D. 24