Engineering Questions with Answers - Multiple Choice Questions

# Mechanical Operations MCQ’s – Relation Between Thickness of Cake and Volume of Filtrate

1 - Question

______ is defined as the ratio of void containing wetting fluid and voids of both fluid.
a) Residual saturation
b) Effective saturation
c) Special saturation
d) Saturation

Explanation: For defining the two phase systems, it is effective saturation Se that is commonly used, S¬e is used defined as the ratio of void containing wetting fluid and voids of both fluid.

2 - Question

Calculate Se, if the wetting fluid void is 2.5 m3 and the void containing both fluids is 8.5 m3?
a) 4.56
b) 1.02
c) 0.75
d) 0.294

Explanation: As Se = 2.5/8.5 = 0.294.

3 - Question

In a super centrifuge, if the radius of the basket is reduced 50% then ____
a) RPM is halved
b) RPM is doubled
c) RPM is tripled
d) No change in RPM

Explanation: If the radius of the basket is decreased by 50% then the revolutions per minute are doubled, than the linear speed of basket.

4 - Question

What are the speeds of basket centrifuge?
a) 15,000 rpm
b) 10,000 rpm
c) 50,000 rpm
d) 1000 rpm

Explanation: Speeds up to 1000 Hz are used to give accelerations 50,000 times the gravitational acceleration, the basket rotates at 15,000 rpm

5 - Question

The degree of separation depends upon the ___
a) Thickness of liquid layer
b) Thickness of solid layer
c) Thickness of cake layer
d) Thickness of strip layer

Explanation: For a given feed rate to the centrifuge, the degree of separation depends upon the thickness of liquid layer at the walls of the baskets.

6 - Question

Mixing involves ____
a) Solid Liquid
b) Solid gas
c) Gas Liquid
d) Solid Liquid gas

Explanation: Mixing involves the mixing of gases, liquid or solids in any possible combination of two or more constituents.

7 - Question

Mixing can be best accomplished by the ____
a) Rotation
b) Agitation
c) Settling
d) Shaking

Explanation: Mixing is accomplished by the rotation action of the impeller in the continuous fluid, also it can be done by agitation but is not economical.

8 - Question

Impellors are divided into ______
a) Initial and Final
b) Tangential and Torsional
c) Centrifuge and Torque

Explanation: Impellors may be roughly be dived into two broad classes mainly axial and radial flow type of impellors, it depends upon angle they make.

9 - Question

Axial flow impellors have _____
a) > 900
b) < 900
c) > 1800
d) < 1800

Explanation: These include all the impellors in which the blade makes an angle of less than 900 with the plane of the rotation.

10 - Question