Engineering Questions with Answers - Multiple Choice Questions

# Mechanical Operations MCQ’s – Open and Closed Circuit Grinding

1 - Question

As consolidation occurs, the rate _____
a) Increases
b) Decreases
c) Remains same
d) Has no change

Explanation: As consolidation occurs, the rate falls off because the resistance to the flow of liquid progressively increases.

2 - Question

The porosity of the particle is ______ at the bottom.
a) Greatest
b) Smallest
d) Same

Explanation: The porosity of the sediments is smallest at the bottom because of the compressive force due to the weight of particles.

3 - Question

Find the rate of sedimentation, if height of sludge and final height are 5.50 m and 2 m, assume the constant b to be 2?
a) 7
b) 5.5
c) 3.5
d) 2

Explanation: As rate is given by b (H-HF) = 2 (5.5-2) = 3*3.5 = 7 kg2m/s.

4 - Question

The shape of vessel has ___ effect on rate of sedimentation.
a) Devastating
b) Vast
c) Little
d) Most

Explanation: Provided that the walls of the vessel are vertical and cross sectional area does not vary with the depth, the shape has little effect on the rate.

5 - Question

The behavior of concentrated suspensions was analyzed by _____
a) Kynch
b) Newton
c) Einstein
d) Duckworth

Explanation: Behavior of concentrated suspensions during sedimentation was analyzed by Kynch, largely using considerations of continuity.

6 - Question

As the concentration approaches the limiting value, sedimentation velocity tends _______
a) Unity
b) Zero
c) Infinity
d) Finalized

Explanation: The sedimentation velocity tends to zero as the concentration approaches a limiting value corresponding to that of the sedimentation.

7 - Question

Kynch showed that the settling rate and concentration of that zone limits the capacity.
a) True
b) Fasle

Explanation: His method was based on the mathematical analysis of the batch settling, which showed that the settling rate and concentration of that zone limits the capacity.

8 - Question

What does the below equation represent? a) Visual velocity
b) Final velocity
c) Upward velocity
d) Lower velocity

Explanation: The rate of upward propagation of such zone is constant and is the function of solids concentration i.e. C and v is the settling velocity.

9 - Question

What does the below equation represent? a) Tangent to settling velocity
b) Angle of nip
c) Angle of settling
d) Sedimentation line

Explanation: The value of settling velocity VL is the slope of the tangent to the curve, this tangent intersects the vertical axis at Z=Z1.

10 - Question

If slope (m) = – tan Ө, therefore
a) VL = 0
b) VL = ZL
c) VL = – tan Ө
d) VL = – tan α