chemical engineering MCQs – Page 315

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 Review each marked answer and report any item that may be outdated or unclear.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
6281. The time of oscillation of a floating body is _________________?
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A. None of these

B. Longer, if Metacentric height is increased

C. Dependent on the buoyant forces only

D. Independent of the Metacentric height

6282. Out of the following flow measuring devices, which one incurs the maximum installation cost as well as pressure loss ?
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A. Orificemeter

B. Rotameter

C. Flow nozzle

D. Venturimeter
6283. Boundary layer exists in flow_________________?
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A. In pipes only

B. Over flat surfaces only

C. Of ideal fluids only

D. Of real fluids
6284. Gear pump_________________?
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A. Is a non-positive displacement pump

B. Can be started with delivery valve closed

C. Is a positive displacement pump

D. Is a centrifugal pump

6285. The discharge through a semi-circular weir varies as (where, H = Head of liquid.) ?
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A. H3/2

B. H2

C. H

D. H1/2

6286. A bed of spherical particles (specific gravity 2.5) of uniform size 1500 ?m is 0.5 m in diameter and 0.5 m high. In packed bed state, the porosity may be taken as 0.4. Erguns equation for the above fluid-particle system (in SI units) is given below : ? P/L = 375 103 VOM + 10.94 106 V2 OM (SI units) If water is to be used as the fluidising medium, the minimum fluidisation velocity, VOM is_________________?
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A. 24 mm/s

B. 28 mm/s

C. 16 mm/s

D. 12 mm/s

6287. Boundary layer separation is caused by the ____________________?
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A. Reduction of pressure below vapour pressure

B. Reduction of boundary layer thickness to zero

C. Adverse pressure gradient

D. Reduction of pressure gradient to zero

6288. Pressure drag does not depend upon the_________________?
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A. All A., B. and C.

B. Length of the body in flow direction

C. Pressure of main flow only

D. Roughness of surface of the body

6289. Pump used for the transportation of molten sodium in a fast breader reactor is a/an __________ pump?
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A. Gear

B. Electromagnetic

C. Reciprocating

D. Plunger

6290. A Newtonian fluid is that__________________?
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A. Which needs a minimum shear, before it starts deforming

B. Which follows Newtons law of motion

C. For which shear & deformation are related as T = ? (?u/?y)

D. None of these

6291. Mass velocity is independent of temperature & pressure, when the flow is______________________?
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A. Steady and the cross-section is unchanged

B. Steady through changing cross-section

C. Unsteady through unchanged cross-section

D. Unsteady and the cross-section is changed

6292. Upto what value of Mach number, a fluid may be considered as incompressible ?
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A. 0.03

B. 3

C. 0.3

D. 10

6293. A 2? gate valve fitted in a pipe is replaced by a similar globe valve. Pressure drop in gate valve was ?p. For the same discharge, the pressure drop across globe valve is__________________?
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A. < ?p

B. > ?p

C. ?p

D. ?p2

6294. Bernoullis equation accounts for the_____________________?
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A. Various momentums

B. Various masses

C. None of these

D. Different forms of mechanical energy
6295. Which of the following equations applies to the fluid flow through a packed bed for very large Reynolds number ?
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A. Hagen-Poiseuille equation

B. Kozeny-Carman equation

C. Blake-Plummer equation

D. Fanning equation

6296. Froude number is the ratio of__________________?
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A. Inertial stress to shear stress

B. Drag stress to shear stress

C. Shear stress to gravitational stress

D. Inertial stress to gravitational stress
6297. The main factor on which the behaviour of a mass of fluidised solid depends mainly is the___________________?
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A. Fluid characteristics

B. Particle size

C. Both A. and B.

D. Neither A. nor B.

6298. Co-efficient of discharge (Cd) is defined as actual discharge/theoretical discharge and is equal to Cc . Cv; where Cc = Co-efficient of contraction and Cv = co-efficient of velocity. Cd of an orifice is usually about__________________?
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A. 0.62

B. 0.82

C. 0.98

D. 0.42

6299. A stream tube is that, which has ______________________ cross-section entirely bounded by stream lines?
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A. A small

B. A circular

C. Any convenient

D. A large

6300. Applying a pressure drop across a capillary results in a volumetric flow rate Q under laminar flow conditions. The flow rate for the same pressure drop, in a capillary of the same length but half the radius is____________________?
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A. Q/16

B. Q/8

C. Q/4

D. Q/2