Mechanical Operations MCQs

Question 1

Which of the following is not used as a surface active agent in a flocculation operation?

Accepted Answer

Quartz

Answer

Sodium silicate

Answer

Lime

Answer

Alumina

Question 2

For crushing of solids, the Rittinger's law states that the work required for crushing is proportional to

Accepted Answer

The new surface created

Answer

The size reduction ratio

Answer

The change in volume due to crushing

Answer

None of these

Question 3

Gelatinous solid (which plug the septum) can be filtered by a __________ filter.

Accepted Answer

Precoat

Answer

Sparkler

Answer

Plate and frame

Answer

Vacuum leaf

Question 4

The process by which fine solids is removed from liquids is termed as

Accepted Answer

Sedimentation

Answer

Decantation

Answer

Flocculation

Answer

Classification

Question 5

Filter aid is used to

Accepted Answer

Increase the porosity of the cake

Answer

Increase the rate of filtration

Answer

Decrease the pressure drop

Answer

Act as a support base for the septum

Question 6

In paint industries, blending of light paste is done by using a

Accepted Answer

Charge can mixer

Answer

Masticator

Answer

Kneader

Answer

None of these

Question 7

The capacity of a classifier in 'tons of solid/hr' is given by (where, A = cross-sectional area, m 2 , V = rising velocity of fluid, m/sec, S = percentage of solids in the suspension by volume, ρ = density of solids, kg/m 3 )

Accepted Answer

3.6 AVS.ρ

Answer

3.6 A.V.ρ

Answer

3.6 A.S.ρ

Answer

3.6 AVS/ρ

Question 8

Pick out the correct statement.

Accepted Answer

Kick's crushing law is, $$\frac{{	ext{P}}}{{	ext{m}}} = {	ext{K}}.\ln \left( {\frac{{{{\overline {	ext{D}} }_{{	ext{sa}}}}}}{{{{\overline {	ext{D}} }_{{	ext{sb}}}}}}} ight)$$

Answer

Plastic chips are called non-cohesive solids

Answer

Communition is a generic term for size enlargement operation

Answer

Energy required in kwh per ton of product, such that 80% of it passes through a 200 mesh screen, is called 'Work index'

Question 9

Trommels separate a mixture of particles depending on their

Accepted Answer

Size

Answer

Density

Answer

Wettability

Answer

Electrical & magnetic properties