chemical engineering mechanical operations MCQs – Page 6

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 Review each marked answer and report any item that may be outdated or unclear.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
101. Moore filter is a ______________ filter ?
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A. Leaf

B. Rotary

C. Sand

D. Press

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

103. In a ball mill, the volume occupied by the balls (when the mill is stopped) is about _______________ percent of the volume of the mill?
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A. 70

B. 50

C. 85

D. 35

104. Energy requirement (per unit mass of material crushed/ground) is highest for__________________?
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A. Jaw crusher

B. Ball mill

C. Fluid energy mill

D. Rod mill

105. The specific cake resistance for compressible sludges is a function of the pressure drop__________________?
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A. Overall

B. None of these

C. Over cake

D. Over medium

106. Size measurement of ultrafine particles can be best expressed in terms of___________________?
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A. Centimetre

B. Micron

C. Screen size

D. Surface area per unit mass
107. Filtration operation carried out by continuous increase of the inlet pressure of slurry, is called the _____________ filtration?
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A. Constant pressure

B. Varying pressure

C. Constant rate

D. Varying rate

108. Theoretical capacity of crushing rolls in tons/hr is given by (where, V = peripheral velocity, m/sec. W = width of rolls, m Dr = distance between rolls ? = density of material to be crushed, kg/m3 here, V =?ND where, N = speed of the rolls in rotation per second (rps) D = diameter of rolls, m) ?
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A. 3.6 W.Dr.?

B. 3.6 V.W.Dr.?

C. 3.6 V.W. ?

D. 3.6 V.W.Dr/?

109. Agglomeration of individual particles into clusters (flocs) is called flocculation. To prevent flocculation, the most commonly used dispersing agents are________________?
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A. Sulphates

B. Bi-carbonates

C. Carbonates

D. Silicates & phosphates
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)

111. _______________ mill is normally used for grinding of talc?
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A. Ring-roll

B. Tube

C. Pebble

D. Compartment

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

116. Which of the following terminology is not used for size reduction of materials to fine sizes or powders ?
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A. Compression

B. Comminution

C. Pulverisation

D. Dispersion

117. Capacity (in tons/hr) of jaw/gyratory crusher is equal to (where, L = length of the receiving opening, cm S = greater width of the discharge opening, cm) ?
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A. L.S

B. 0.087 L.S

C. L.S/0.087

D. 0.01 L.S

118. A _______________ employs a set of screen across a flow channel for the separation of dirt/rust from a flowing liquid stream?
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A. Strainer

B. Thickener

C. Clarifier

D. Classifier

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

120. As per Taggarts formula, the capacity (kg/hr) of Jaw & Gyratory crushers (for gapes of 10 to 60 cms) is equal to (where, L = Length of feed opening, cms S = Maximum width of discharge opening, cms) ?
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A. ?(LS)

B. 250 LS

C. LS

D. 93 LS