Engineering Questions with Answers - Multiple Choice Questions

# Mechanical Operations MCQ’s – Theory of Filtration

1 - Question

The ratio of void volume and total surface area of particles is defined as _____
a) Resistance
c) Repulsion
d) Void age

Explanation: The hydraulic radius which is defined as the flow area per unit wetted perimeter and is represented by RH.

2 - Question

What does the ε represents?
a) Porosity
b) Density
c) Viscosity
d) Acidity

Explanation: The ratio of void volume and the total volume is defined as the porosity, which is denoted by ε.

3 - Question

Calculate ε, if the total area is 45 m2 and the void area is 100 m2?
a) 10.5
b) 0.45
c) 2.222
d) 0.89

Explanation: As we know ε = void area/total area = 100/45 = 2.222.

4 - Question

Calculate the hydraulic radius, if porosity is 0.6 and specific gravity is 1.50?
a) 1
b) 0.6
c) 0.2
d) 1.8

Explanation: As we know that ε/sp (1- ε) = 0.6/1.50(1-0.6) = 1.

5 - Question

____ of the liquid is defined as volumetric flow rate of the liquid divided by the total area.
a) Final velocity
b) Total volume
c) Superficial velocity
d) Wetted perimeter

Explanation: The superficial velocity is defined as the volumetric rate and liquid divided by total or empty cross sectional area Usup.

6 - Question

What does the below equation represent?

a) Resistance
c) Repulsion
d) Void age

Explanation: Here ε is the void fraction sometimes called porosity of the bed and Sp is the specific surface area of the particles.

7 - Question

What does the below represent?
t= f tc
a) Cake formation
b) Drum rotation
c) Initial extraction
d) Extra time

Explanation: The above equation represents the time taken for cake formation, if tc is the time for one full rotation of the drum.

8 - Question

____ is defined as the volume of void filled and total volume.
a) Upper velocity
b) Saturation
c) Residual saturation
d) Superficial velocity

Explanation: The saturation (S) is usually defined with respect to the wetting fluid and is therefore the fractional volume of voids occupied by the wetting fluid.

9 - Question

____ is the maximum volume wetted to ratio of total volume.
a) Residual saturation
b) Saturation
c) Residual saturation
d) Superficial velocity

Explanation: The residual saturation (SF) is defined as the ratio of maximum volume wetting fluid eliminated from flow and total volume of voids.

10 - Question

Calculate S, if the voids filled are 40 m3 and having 50 m3 of total volume?
a) 0.8
b) 1.25
c) 40
d) 50