chemical engineering fluid mechanics for chemical chemical engineering MCQs – Page 15

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 Review each marked answer and report any item that may be outdated or unclear.

chemical engineering fluid mechanics for chemical chemical engineering Mcqs
281. With increasing flow rate, the hydraulic efficiency of a centrifugal pump__________________?
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A. Remains constant

B. Monotonically decreases

C. Decreases and then increases

D. Increases and then decreases

282. Non-colloidal solution is an example of the _______________ fluid?
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A. Pseudo-plastic

B. Non-Newtonian

C. Newtonian

D. Dilatent

283. With increase in the shear rate, the apparent viscosity of pseudo-plastic fluids__________________?
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A. May increase or decrease; depends on the magnitude of shear rate

B. Decreases

C. Remain same

D. Increases

284. Colebrook equation for friction factor in turbulent flow is given by, f-0.5 = -4 loge [(?/D) + (1.26/NRe ?F). It reduces to Nikuradse equation for a value of (?/D) equal to __________________?
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A. 0

B. ?

C. 0.5

D. 1
285. Capillary rise of mercury in a small diameter tube is proportional to (where, d = diameter of the tube, ? = surface tension of mercury)____________________?
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A. 1/?

B. d

C. ?

D. 1/d

286. A Rotameter works on the principle of _______________ pressure drop?
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A. Constant

B. Variable

C. Both A. & B.

D. Neither A. nor B.

287. Which law is followed by the velocity distribution in the turbulent boundary layer ?
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A. Logarithmic law

B. Linear law

C. None of these

D. Parabolic law

288. Bernoullis equation accounts for the_____________________?
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A. Different forms of mechanical energy

B. Various masses

C. Various momentums

D. None of these

289. In turbulent flow, the__________________?
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A. Momentum transfer is on molecular scale only

B. Shear stresses are generally larger than in a similar laminar flow

C. Shear stress is caused more effectively by cohesion than momentum transfer

D. Fluid particles move in an orderly manner

290. 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, in actual operation, the above bed has a height = 1 m. What is the porosity of the fluidised bed ?
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A. 0.8

B. 0.5

C. 0.7

D. 0.2

291. For a stable equilibrium of a submerged body (where, G and B are centres of gravity & buoyancy respectively) ?
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A. None of these

B. B is above G

C. G is above B

D. B & G coincide

292. The ratio of the depth of flow to the hydraulic radius for the most economical trapezoidal section, in open channel flow is_____________________?
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A. 2

B. 1

C. 1.5

D. 0.5

293. In a stabilised soap bubble, pressure inside it compared to external pressure is________________?
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A. Less

B. Same

C. Unpredictable

D. More
294. Which of the following is dimensionless ?
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A. Fanning friction factor

B. Specific volume

C. None of these

D. Angular velocity

295. Boundary layer thickness in laminar flow over a flat plate increases as(where, d = distance from the leading edge.) ?
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A. d2

B. d1/3

C. d2/3

D. ?d
296. Head developed by a centrifugal pump depends on its___________________?
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A. Speed

B. Impeller diameter

C. Both A. and B.

D. Neither A. nor B.

297. Piezometric head is the sum of the ______________ heads?
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A. None of these

B. Elevation & kinetic energy

C. Elevation & pressure

D. Kinetic energy & pressure

298. Which of the following has the maximum compression ratio ?
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A. Blower

B. Vacuum pump

C. Compressor

D. Fan

299. In power law, ? = [A (du/dy)2 + B] then the fluid is__________________?
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A. Rheopectic

B. Dilatant

C. Thixotropic

D. Newtonian
300. The line of action of the buoyant force acts through the____________________?
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A. None of these

B. Centroid of the volume of any floating body

C. Centroid of the displaced volume of fluid

D. Centre of gravity of a submerged body