Mechanical Operations MCQs

Question 1

Size reduction of fibrous materials like wood, asbestos, mica etc. is done by a disintegrator exemplified by the

Accepted Answer

Cage mill

Answer

Blake jaw crusher

Answer

Stamp mill

Answer

Bradford's breaker

Question 2

Ore concentration by jigging is based on the difference in the __________ of the particles.

Accepted Answer

Specific gravities

Answer

Wettability

Answer

Shape

Answer

None of these

Question 3

Size reduction does not occur due to compression in case of

Accepted Answer

Rod mills

Answer

Gyratory crushers

Answer

Jaw crushers

Answer

Smooth roll crushers

Question 4

Which of the following is not an industrial screening equipment?

Accepted Answer

Sharpies centrifuge

Answer

Vibrating screen

Answer

Grizzly

Answer

Trommel

Question 5

Wet grinding in a revolving mill __________ as compared to dry grinding.

Accepted Answer

Increases capacity

Answer

Gives less wear on chamber walls

Answer

Requires more energy

Answer

Complicates handling of the product

Question 6

The specific surface of spherical particles is given by (where D and $$\rho $$ are diameter and density of particle).

Accepted Answer

$$\frac{6}{{{	ext{D}}.ho }}$$

Answer

$$\frac{2}{{{	ext{D}}.ho }}$$

Answer

$$\frac{4}{{{	ext{D}}.ho }}$$

Answer

$$\frac{{12}}{{{	ext{D}}.ho }}$$

Question 7

Which of the following is the softest material?

Accepted Answer

Talc

Answer

Feldspar

Answer

Corundum

Answer

Calcite

Question 8

A propeller agitator

Accepted Answer

Produces mainly axial flow

Answer

Is used for mixing high viscosity pastes

Answer

Runs at very slow speed (2 rpm)

Answer

All of the above

Question 9

During washing of filter at the end of constant pressure filtration, the rate of washing equals the rate of filtration

Accepted Answer

At the end of filtration

Answer

At time zero

Answer

When half the filtrate has been obtained

Answer

At the end of filtration, but decreases with time subsequently