Mechanical Operations MCQ Questions & Answers | Chemical Engineering

A. Close circuit grinding is more economical than open circuit grinding

B. Cod oil, beef tallow or aluminium stearates are used as grinding aids in cement 'industries'

C. The equipment used for the removal of traces of solids from a liquid is called a classifier

D. Size enlargement is a mechanical operation exemplified by medicinal tablet making

A. Reduction ratio

B. Capacity

C. Both A & B

D. Neither A nor B

A. Dry

B. Wet

C. Ultrafine

D. Intermediate

A. No units (dimensionless)

B. kWh/ton

C. kW/ton

D. $${\text{kWh}}.{{\text{m}}^{\frac{1}{2}}}/{\text{ton}}$$

A. Oversizes are present in undersize fraction

B. Undersizes are retained in oversize fraction

C. Screen is plugged with solid particles

D. Screen capacity is abruptly increased

A. 0.5

B. 1

C. < 1

D. $$\sqrt 3 $$

A. Cummulative analysis for determining surface area is preferred over differential analysis, because of the assumption that "all particles in a simple fraction equal in size" is not needed for cummulative anslysis unlike differential anlaysis

B. A gate diagram is a plot of cummulative percent by weight undersize vs. the reciprocal of diameter, in which the area beneath the curve represents the surface

C. Capacity of crusher in choke feeding is increased

D. Rolling of pebbles/balls from top to bottom of the heap in tumbling mills is called 'cascading and throwing of the balls through the air to the toe of the heap is called 'cataracting'

A. Recovery/rejection

B. Recovery

C. Rejection

D. None of these

A. Run at very high rpm

B. Suitable for sticky materials

C. Suitable for highly abrasive materials

D. All of the above

A. Secondary

B. Fine

C. Primary

D. Ultrafine