chemical engineering mechanical operations Mcqs
102. Highly viscous liquids & pastes are agitated by________________?
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A. Multiple blade paddles

B. Turbine agitators

C. None of these

D. Propellers

110. Half the angle of nip, (?), for a roll crusher is given by (where, dr, dp and df are diameters of crushing rolls, feed particles and rolls gap respectively) ?
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A. cos ? = (dr + dp)/(dr + df)

B. cos ? = (dr + df)/(dr + dp)

C. sin ? = (dr + dp)/(dr + df)

D. tan ? = (dr + dp)/(dr + df)

112. Reciprocal of sphericity is termed as the________________?
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A. Surface area per unit mass

B. Sauter diameter

C. Shape factor

D. Specific surface ratio

113. Gravity settling process is not involved in the working of a________________?
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A. Classifier

B. Dorr-thickener

C. Hydrocyclone

D. Sedimentation tank

114. Filtration of water in a paper mill is done by a/an _______________ filter?
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A. Vacuum leaf

B. Sparkler

C. Open sand

D. Plate and frame

115. During filtration operation, the filtrate encounters the resistance of the ___________________?
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A. Cake

B. Filter medium

C. Channel carrying the slurry to the upstream side of the cake and filtrate away from the filter

D. All A., B. and C.

E. ium

119. A screen is said to be blinded, when the___________________?
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A. Over-sizes are present in undersize fraction

B. Screen is plugged with solid particles

C. Under-sizes are retained in oversize fraction

D. Screen capacity is abruptly increased

121. Which of the following is not used as a filter medium in case of corrosive liquids?
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A. Metal cloth of monel or stainless steel

B. Glass cloth

C. Cotton fabric

D. Nylon

122. Cumulative analysis for determining surface is more precise than differential analysis, because of the_______________?
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A. Fact that screening is more effective

B. Assumption that all particles in a single fraction are equal in size, is not needed

C. Assumption that all particles in a single fraction are equal in size

D. None of these

124. Grinding characteristic of a material is given by its___________________?
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A. HGI

B. Angle of repose

C. Shatter index

D. Abrasion index

126. In case of a ball mill ?
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A. None of these

B. Coarse feed requires a larger ball

C. Operating speed should be more than the critical speed

D. Fine feed requires a larger ball

127. If radius of a batch basket centrifuge is halved & the r.p.m. is doubled, then the_________________?
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A. Linear speed of the basket is doubled

B. Linear speed of the basket is halved

C. Capacity of centrifuge is increased

D. Centrifugal force is doubled
128. Which of the following achieves the least reduction ratio for a given feed size ?
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A. Gyratory crusher

B. Jaw crusher

C. Cone crusher

D. Roll crusher
131. Paddle agitator_________________?
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A. None of these

B. Produces axial flow

C. Moves at very high speed

D. Is suitable for mixing low viscosity liquids
135. The most suitable equipment for the transportation of 200 mesh size particles is a _______________?
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A. Screw conveyor

B. Bucket elevator

C. Pneumatic conveyor

D. Belt conveyor

136. Removal of activated carbon from glycerine is done by _________________?
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A. Rotary vacuum filter

B. Batch basket centrifuge

C. None of these

D. Plate and frame filter
141. To remove dirt from the flowing fluid, we use a ____________________?
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A. Coagulant

B. Strains

C. Clarifier

D. Gravity settler

142. Mixing mechanism employed in a pan mixer is by ________________?
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A. Kneading

B. None of these

C. Dispersion

D. Mulling
144. As particle size is reduced__________________?
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A. Screening becomes progressively more difficult

B. Capacity and effectiveness of the screen is increased

C. Screening becomes progressively easier

D. None of these

147. In constant pressure filtration ?
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A. Rate of filtration decreases with time

B. Rate of filtration is constant

C. Resistance decreases with time

D. Rate of filtration increases with time

149. Which of the following is not a wet classifier ?
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A. Sharpies super-centrifuge

B. None of these

C. Dorr Oliver rake classifier

D. Hydrocyclones