Engineering Questions with Answers - Multiple Choice Questions
Mechanical Operations MCQ’s – Size Reduction Equipments
1 - Question
For crushing rolls, α is_____
a) Angle of bend
b) Angle of Nip
c) Angle of stamp
d) Angle of Camp
View Answer
Answer: b
Explanation: Angle of nip is the angle formed by the tangents to the roll faces at the point of contact with the particle to be crushed.
2 - Question
What is α for average conditions?
a) 0.961
b) 160
c) 170
d) 200
View Answer
Answer: b
Explanation: For average conditions the angle of nip α is 160 i.e. cos α = 0.961.
3 - Question
How can be the angle of nip calculated?
a) r+d/r+R
b) R+r/r+d
c) D/r+d
d) R/r+d
View Answer
Answer: a
Explanation: The angle of nip i.e. cos α = r+d/r+R, where R and r are the radius of feed particle and the roll and d is the diameter of largest possible product.
4 - Question
Calculate α. If radius of feed and roll are 100 mm and 500 mm respectively and largest particle is 5 mm?
a) 41.1
b) 32.75
c) 16
d) 20
View Answer
Answer: b
Explanation: As Cos α = r+d/r+R = 500+5/100+500 = 0.841 = arcos (0.841) = 32.750.
5 - Question
Which of the following works on the principle of shearing?
a) Ball mill
b) Roll crusher
c) Toothed crusher
d) Rod mill
View Answer
Answer: c
Explanation: The toothed crusher works on the principle of the shearing, while all other mentioned work on the principle of compression.
6 - Question
The feed size of a toothed crusher ranges from ____
a) 20 inches
b) 10 inches
c) 30 inches
d) 40 inches
View Answer
Answer: a
Explanation: The feed size of a toothed crusher ranges from 20 inches, while product size ranges from 50 to 200 mm.
7 - Question
Which of the following works on the principle of impact?
a) Ball mill
b) Roll crusher
c) Jaw crusher
d) Gyratory Mill
View Answer
Answer: a
Explanation: The ball mill works on the principle of impact, it consists of the horizontal cylinder lined with steel or high carbon plates.
8 - Question
The shell diameter ranges from ____
a) 1 to 2.5 m
b) 3 to 4.25 m
c) 2 to 3 m
d) 5 to 10 m
View Answer
Answer: b
Explanation: The shell diameter ranges from 3 to 4.25 m and while the balls diameter varies from 1 inch to 5 inches in the diameter.
9 - Question
The feed size of a ball mill ranges from _____
a) 50 mm
b) 100 mm
c) 200 mm
d) 300 mm
View Answer
Answer: a
Explanation: The feed size of a ball mill ranges from 50 mm, while the product size ranges from 100 to 200 mesh screen.
10 - Question
As the rate of feed increases, the size reduction ____
a) Increases
b) Remains constant
c) Equals
d) Decreases
View Answer
Answer: d
Explanation: With high rate of feed, less size reduction is done since the material is retained in the mill for shorter time.