chemical engineering mechanical operations MCQs – Page 11

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 Review each marked answer and report any item that may be outdated or unclear.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
201. Run of mine (ROM) coal is crushed by a _________________________ for use in domestic ovens?
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A. Hammer crusher

B. Jaw crusher

C. Ball mill

D. Tube mill

202. Apron conveyors are used for ___________________ ?
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A. Heavy loads & short runs

B. Heavy loads & long runs

C. None of these

D. Small loads & long runs

203. Separation of solid suspended in liquid into a supernatant clear liquid and a denser slurry employs a process termed as the___________________?
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A. Flocculation

B. Sedimentation

C. Coagulation

D. Clarification

204. Bond crushing law_________________?
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A. States that the work required to form particle of any size from very large feed is proportional

B. Calls for relatively less energy for the smaller product particles, than does the Rittinger law

C. Is less realistic in estimating the power requirements of commercial crushers

D. the square root of the volume to surface ratio of the product

E. States that the work required for the crushing is proportional to the new surface created

205. A tube mill as compared to a ball mill__________________?
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A. Gives finer size reduction but consumes more power

B. All A., B. and C.

C. Has larger length/diameter ratio (>2 as compared to 1 for ball mill)

D. Employs smaller balls

206. Ultracentrifuges running at speeds upto 100000 rpm is normally used for the_____________________?
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A. Concentration of rubber latex

B. Dewaxing of lubricating oil

C. Separation of cream from milk

D. Separation of isotopes based on their density or molecular weights difference
207. The main size reduction operation in ultrafine grinders is_____________?
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A. Cutting

B. Compression

C. Attrition

D. Impact

208. Rittinger number which designates the new surface produced per unit of mechanical energy absorbed by the material being crushed, depends on the ______________________?
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A. All A., B. and C.

B. Elastic constant of the material

C. State or manner of application of the crushing force

D. Ultimate strength of the material

209. Which of the following relationships between co-efficient of friction (?) between rock & roll and a (half of the angle of nip) of the particle to be crushed is correct ?
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A. ? > tan 2?

B. ? ? tan ?

C. ? ? tan ?

D. ? > tan ?

210. Ball mills and tube mills with flint or porcelain balls are used for size reduction of_______________?
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A. Limestone

B. Rubber

C. Asbestos

D. Non-metallic ores
211. Which of the following conveyors cannot be recommended for transportation of abrasive materials ?
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A. Flight conveyor

B. Belt conveyor

C. Chain conveyor

D. Apron conveyor

212. In case of grinding in a ball mill__________________?
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A. Its capacity decreases with increasing fineness of the products

B. All A., B. and C

C. Wet grinding achieves a finer product size than dry grinding

D. Grinding cost and power requirement increases with increasing fineness of the products

213. In washing type plate and frame filter press, the ratio of washing rate to the final filtrate rate is__________________?
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A. 2-Jan

B. 4

C. 1

D. 1/4
214. To get ultrafine particles, the equipment used is a _________________?
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A. Hammer crusher

B. Fluid energy mill

C. Ball mill

D. Rod mill

215. The opening of a 200 mesh screen (Taylor series) is__________________?
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A. 0.0074 cm

B. 74 milli-microns

C. 0.0047 cm

D. 0.0074 mm

216. The sphericity of a solid particle of cubical shape is ___________________?
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A. ?

B. (?/6)1/2

C. ?/3

D. (?/6)1/3
217. Size reduction of _____________ is accomplished in steam heated rollers and roll crushers?
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A. Resins

B. Hard rubber

C. Waxes

D. Gums

218. A fluid energy mill is used for_________________?
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A. Grinding

B. Crushing

C. Cutting

D. Ultra grinding
219. Separation of isotopes is generally done using a/an _______________ centrifuge?
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A. Ultra

B. Disk-bowl

C. Both A. & B.

D. Neither A. nor B.

220. In screen analysis, the notation +5 mm/-10 mm means particles passing through ____________________?
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A. 10 mm screen and retained on 5 mm screen

B. 5 mm screen and retained on 10 mm screen

C. Both 5 mm and 10 mm screens

D. Neither 5 mm nor 10 mm screen