Engineering Questions with Answers - Multiple Choice Questions

Home » MCQs » Chemical Engineering » Mechanical Operations MCQ’s – Theory of Filtration

# Mechanical Operations MCQ’s – Theory of Filtration

The ratio of void volume and total surface area of particles is defined as _____

a) Resistance

b) Hydraulic radius

c) Repulsion

d) Void age

**
View Answer**

Answer: b

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

What does the ε represents?

a) Porosity

b) Density

c) Viscosity

d) Acidity

**
View Answer**

Answer: a

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

Calculate ε, if the total area is 45 m^{2} and the void area is 100 m2?

a) 10.5

b) 0.45

c) 2.222

d) 0.89

**
View Answer**

Answer: c

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

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

**
View Answer**

Answer: a

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

____ 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

**
View Answer**

Answer: c

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

What does the below equation represent?

a) Resistance

b) Hydraulic radius

c) Repulsion

d) Void age

**
View Answer**

Answer: b

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

What does the below represent?

t= f t_{c}

a) Cake formation

b) Drum rotation

c) Initial extraction

d) Extra time

**
View Answer**

Answer: a

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

____ is defined as the volume of void filled and total volume.

a) Upper velocity

b) Saturation

c) Residual saturation

d) Superficial velocity

**
View Answer**

Answer: b

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.

____ is the maximum volume wetted to ratio of total volume.

a) Residual saturation

b) Saturation

c) Residual saturation

d) Superficial velocity

**
View Answer**

Answer: a

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

Calculate S, if the voids filled are 40 m^{3} and having 50 m^{3} of total volume?

a) 0.8

b) 1.25

c) 40

d) 50

**
View Answer**

Answer: a

Explanation: As we know that S = void volume/total volume = 40/50 = 0.8.