Mechanical Operations MCQs

Question 1

Paddle agitator

Accepted Answer

Is suitable for mixing low viscosity liquids

Answer

Produces axial flow

Answer

Moves at very high speed

Answer

None of these

Question 2

Pick out the material having minimum Rittinger's number.

Accepted Answer

Quartz

Answer

Calcite

Answer

Pyrite

Answer

Galena

Question 3

Separation of a suspension or slurry into a supernatant clear liquid (free from particles) and a thick sludge containing a high concentration of solid is called

Accepted Answer

Sedimentation

Answer

Classification

Answer

Clarification

Answer

Decantation

Question 4

Power consumption during turbulent flow in agitation tank is proportional to the __________ of the liquid.

Accepted Answer

Density

Answer

Viscosity

Answer

Thermal conductivity

Answer

Surface tension

Question 5

In case of a hammer crusher,

Accepted Answer

All of the above

Answer

Crushing takes place by impact breaking

Answer

Maximum acceptable feed size is 30 cms

Answer

Reduction ratio can be varied by adjusting the distance from cage to hammers

Question 6

Which of the following is a coarse crusher?

Accepted Answer

Gyratory crusher

Answer

Smooth roll crusher

Answer

Toothed roll crusher

Answer

Tube mill

Question 7

Percentage of drum submerged in the slurry in case of rotary drum filter is

Accepted Answer

30

Answer

3

Answer

85

Answer

25

Question 8

Sulphuric acid mist is arrested by using a __________ scrubber.

Accepted Answer

Venturi

Answer

Packed wet

Answer

Hollow wet

Answer

Co-current

Question 9

Rod mills employed for grinding

Accepted Answer

All of the above

Answer

Employ a steel shell having L/D ratio of 1.5 to 3.0

Answer

Is useful for handling sticky materials

Answer

Employ steel rods of 2-12 cms diameter extending over full length of the mill