chemical engineering MCQs – Page 325

Practise multiple-choice questions from chemical engineering for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering Mcqs
6481. What is the speed of sound (m/sec) in ordinary water ?
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A. 3000

B. 330

C. 1000

D. 1500
6482. If three pipes of different diameters, lengths & friction factors are connected in parallel, then (where, Q = flow rate, V= fluid velocity f = friction factor). ?
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A. Q = Q1 + Q2 + Q3

B. Q1 = Q2 = Q3

C. V1 = V2 = V3

D. f = f1 + f2 + f3

6483. The Prandtl mixing length is_________________?
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A. Zero at the pipe wall and is a universal constant

B. Independent of radial distance from the pipe axis

C. Useful for computing laminar flow problems

D. Independent of the shear stress

6484. Bed pressure drop in an air fluidised bed of catalyst particles (?p = 200 kg/m3, Dp = 0.05 cm) of 60 cm bed depth and bed porosity of 0.5 expressed in cm of water (manometer) is________________?
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A. 30

B. 90

C. 60

D. 45

6485. Which of the following equations as suggested by Colebrook and White gives the increase in roughness of a new surface (?0) with age/time (t) (where, ? = roughness of the surface after timet. ? = a co-efficient to be experimentally determined) ?
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A. ? = ?0 + ?.t2

B. ? = ?0 + ?.t3

C. ? = ?0 + ?.t4

D. ? = ?0 + ?.t
6486. Volute of a centrifugal pump should be designed in a fashion, such that the________________?
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A. None of these

B. Kinetic head gets converted into static head

C. Mean velocity remains constant

D. Moving stream gradually reduces velocity

6487. The unit of velocity head is_________________?
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A. ft-lbf/sec

B. ft-lbf/lb

C. ft-lb/ft3

D. ft-lb/sec

6488. A floating/submerged body is always stable, if its centre of gravity___________________?
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A. Lies above its centre of buoyancy

B. Lies above its metacentre

C. Lies below its centre of buoyancy

D. And centre of buoyancy coincide

6489. Cavitation can be prevented by________________?
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A. Maintaining the suction head sufficiently greater than the vapour pressure

B. Maintaining suction head lower than the vapour pressure

C. Suitably designing the pump

D. Maintaining suction head = developed head

6490. Permanent loss in a Venturimeter is about ___________ percent of the pressure drop in the upstream cone?
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A. 10

B. 1

C. 40

D. 70

6491. Priming is needed in a ______________ pump?
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A. Centrifugal

B. Diaphragm

C. Reciprocating

D. Gear

6492. For the same terminal conditions and valve size, the pressure drop in a fully opened globe valve as compared to that in a gate valve is___________________?
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A. Less

B. More

C. Equal

D. Either A. or B.; depends on the viscosity of the fluid

6493. The distribution of shear stress in a stream of fluid in a circular tube is_____________________?
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A. Linear with radius for turbulent flow only

B. Linear with radius for laminar flow only

C. Linear with radius for both laminar & turbulent flow

D. Parabolic with radius for both laminar & turbulent flow

6494. Which of the following is dimensionless ?
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A. Specific volume

B. Angular velocity

C. None of these

D. Fanning friction factor
6495. Pumping of a corrosive liquid is generally preferred to be done by a ______________ pump, as it can be made of a variety of materials including plastics?
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A. Piston

B. Positive displacement

C. Sump

D. Gear
6496. Prandtl number is a measure of the__________________?
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A. Cp/Cv of a fluid

B. Elastic force to pressure force in the fluid flow

C. Heat conduction to viscosity of a fluid

D. Inertial force to elastic force in the fluid flow

6497. Where does the maximum stress occur in case of laminar flow of incompressible fluid in a closed conduit of diameter d ?
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A. At the wall

B. At the centre

C. At d/8 from the wall

D. At d/4 from the wall

6498. The peripheral velocity at inlet of a centrifugal pump having inlet diameter of 25 cms and rotating at 950 rpm is __________ m/sec?
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A. 186.2

B. 1.8

C. 736.4

D. 12.4
6499. Disc compensators are provided in large diameter fuel gas carrying pipelines to_________________?
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A. Make the pipe joint leak-proof

B. Account for the pressure variation side the pipeline

C. Keep the pipe in proper orientation

D. Account for contraction/expansion of pipe due to temperature changes of the surroundings
6500. Which of the following is not an advantage of fluidisation from transfer operation point of view ?
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A. Minimisation of temperature variation

B. Intimate contact of the fluid with all parts of the solid particles

C. Lower fluid pumping power requirement

D. Prevention of particle segregation