Mechanical Operations MCQs

Question 1

The reduction ratio for grinders is defined as (where, D f and D p are average diameters of feed and product respectively).

Accepted Answer

$$\frac{{{{	ext{D}}_{	ext{f}}}}}{{{{	ext{D}}_{	ext{p}}}}}$$

Answer

$$\frac{{{{	ext{D}}_{	ext{p}}}}}{{{{	ext{D}}_{	ext{f}}}}}$$

Answer

D f - D p

Answer

None of these

Question 2

Pick out the correct statement.

Accepted Answer

Both B and C

Answer

The capacity and the effectiveness of a screen are the same

Answer

The capacity and the effectiveness of screen are opposing factors

Answer

The screening surface of a

Question 3

The specific surface of sherical particles is proportional to (where, D p = diameter of particle).

Accepted Answer

$$\frac{1}{{{{	ext{D}}_{	ext{p}}}}}$$

Answer

$${{	ext{D}}_{	ext{p}}^2}$$

Answer

D p

Answer

$$\frac{1}{{{	ext{D}}_{	ext{p}}^2}}$$

Question 4

Mixing mechanism employed in a pan mixer is by

Accepted Answer

Mulling

Answer

Kneading

Answer

Dispersion

Answer

None of these

Question 5

__________ is defined as the geometric mean of the relative rejections and the relative recoveries of two minerals.

Accepted Answer

Selectivity index

Answer

Separation efficiency

Answer

Concentration ratio

Answer

None of these

Question 6

The study on washability of coal is done by using the __________ technique.

Accepted Answer

Heavy media separation

Answer

Tabling

Answer

Elutriation

Answer

None of these

Question 7

Grinding characteristic of a material is given by its

Accepted Answer

HGI

Answer

Angle of repose

Answer

Shatter index

Answer

Abrasion index

Question 8

Xanthates are used in the froth floatation process as a/an

Accepted Answer

Collector

Answer

Conditioner

Answer

Frother

Answer

Activator

Question 9

For spheres, the surface shape factor is given by (where, A = area, V = volume, and D = diameter)

Accepted Answer

π(=A/D²)

Answer

π/6(=V/D³)

Answer

AD/V

Answer

None of these