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
View Answer
Answer: b
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
c) Broader
d) Same
View Answer
Answer: b
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
View Answer
Answer: a
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
View Answer
Answer: c
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
View Answer
Answer: a
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
View Answer
Answer: b
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
View Answer
Answer: a
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
View Answer
Answer: c
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
View Answer
Answer: a
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
View Answer
Answer: d
Explanation: We know that ZI – ZL = – Өi tan Ө, hence VL can be equal to – tan α.