chemical engineering mechanical operations MCQs – Page 17

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 Review each marked answer and report any item that may be outdated or unclear.

chemical engineering mechanical operations Mcqs

321. A compressible cake has the_________________?
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A. Maximum porosity at the filter medium

B. Maximum porosity at the upstream side

C. None of these

D. Same porosity throughout the cake thickness

322. Traces of liquid tar fog present in coke oven gas is separated using____________________?
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A. Electrostatic precipitator

B. None of these

C. Strainer

D. Cyclone separator

323. Cyclones are used primarily for separating_________________?
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A. Solids from solids

B. Solids from fluids

C. Liquids

D. Solids

324. The constants (Kb, Kr and Kk) used in the laws of crushing (i.e., Bonds law, Rittingers law and Kicks law) depend upon the_________________?
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A. Feed material

B. Type of crushing machine

C. Both A. & B.

D. Neither A. nor B.

325. In case of a hammer crusher ?
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A. Reduction ratio can be varied by adjusting the distance from cage to hammers

B. All A., B. and C.

C. Crushing takes place by impact breaking

D. Maximum acceptable feed size is 30 cms

326. Separation of solid particles based on their densities is called_________________?
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A. Clarification

B. Sizing

C. Dispersion

D. Sorting

327. For separation of sugar solution from settled out mud, we use a ___________________ filter?
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A. Rotary drum vacuum

B. Centrifugal

C. Plate and frame

D. Sparkler

328. Sphericity of a cubical particle, when its equivalent diameter is taken as the height of the cube, is ________________ ?
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A. ?3

B. ?2

C. 1

D. 0.5

329. During size reduction by a jaw crusher, the energy consumed decreases with the__________________?
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A. None of these

B. Decreasing machine capacity

C. Increasing size of feed at constant reduction ratio

D. Decreasing size of product at constant size of feed

330. What is the critical rotation speed in revolutions per second, for a ball mill of 1.2 m diameter charged with 70 mm dia balls ?
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A. 1

B. 0.5

C. 0.66

D. 2.76

331. In froth floatation, chemical agent added to cause air adherence is called___________________?
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A. Modifier

B. Collector

C. Activator

D. Frother

332. Pick out the correct statement ?
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A. The operating cost of shaking screen is more than that of a vibrating screen

B. Removal of iron from ceramic material is necessitated (by magnetic separation method) so as

C. Asphalt is best crushed using toothed roll crusher

D. avoid discolouration of ceramic products</strong>

E. Screen capacity does not depend upon the specific gravity of the minerals

333. The equivalent diameter of channel of a constant non-circular cross-section of 3 cm by 6 cm will be _______________ cms?
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A. 20

B. 8

C. 12

D. 2

334. Pick out the wrong statement pertaining to the roll crushers?
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A. Maximum feed size determines the required roll diameter

B. For hard materials crushing, the reduction ratio should not exceed 4

C. Both the rolls run necessarily at the same speed

D. Reduction ratio and differential roll speed affect production rate & energy consumed per unit

E. surface produced

335. Sorting classifiers employing differential settling methods for separation of particles make use of the differences in their_________________?
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A. Densities

B. Terminal velocities

C. Particle sizes

D. None of these

336. According to Bond crushing law, the work required to form particle of size D from very large feed is (where (S/V)p and (S/V)f are surface to volume ratio of the product and feed respectively) ?
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A. (S/V)f

B. ?(S/V)p

C. (S/V)p

D. (S/V)2p

337. Pick out the wrong statement ?
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A. The angle of nip (2?) is the angle between roll faces at the level where they will just take hold

B. duct

C. Gape is the greatest distance between the crushing surfaces or the jaws

D. a particle and draw it in the crushing zone

E. ated by crushing</strong>

F. Reduction ratio is the ratio of the maximum size of the particles in the feed to that in the

338. Which of the following is not an ultrafine grinder (colloid mill) ?
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A. Micronizers

B. Toothed roll crusher

C. Hammer mills with internal classification

D. Agitated mills and fluid energy mills

339. Pick out the wrong statement pertaining to the turbine agitator ?
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A. blade length is l/4th of agitator diameter (with central disc, it is l/8th of the agitator

B. Turbine agitator should be located at a height not less than one agitator diameter length from

C. tators should be used

D. Pitched blade turbine agitator gives only radial flow with complete absence of the axial flow

E. meter)

F. bottom. If the depth of liquid in the tank is more than twice the agitator diameter, two

340. Equivalent diameter of a particle is the diameter of the sphere having the same __________________?
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A. Ratio of volume to surface as the particle

B. None of these

C. Ratio of surface to volume as the actual volume

D. Volume as the particle

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