Engineering Questions with Answers - Multiple Choice Questions

Mechanical Operations MCQ’s – Advantages of Ball Mill

1 - Question

____ is an open container usually cylindrical with uniform openings.
a) Bowel
b) Screen
c) Magnifier
d) Shredder

View Answer

Answer: b
Explanation: A screen can be called as an open container usually cylindrical with uniform openings, it is normally made of wire mesh cloth.




2 - Question

What is the square opening between screens called?
a) Aperture
b) Abscissa
c) Ordinate
d) Footrope

View Answer

Answer: a
Explanation: The size of square opening the length of clear of clear space between individual wires is called as aperture size of the screen.




3 - Question

How is screen effectiveness defined?
a) Maximum*Minimum
b) Retained*Captured
c) Recovery*Rejection
d) Retained* Rejection

View Answer

Answer: c
Explanation: The one of the most general methods of defining classifying screens effectiveness EC is product of Recovery and Rejection.




4 - Question

 In an open grinding operation, the material is passed through crusher only _____
a) Once
b) Twice
c) Not passed
d) Infinite

View Answer

Answer: a
Explanation: Material is passed only once through the crusher in an open grinding operation, due to which less separation takes place.




5 - Question

Which of the following resides more energy?
a) Closed Circuit
b) Open circuit
c) Bi-lateral
d) By-pass

View Answer

Answer: b
Explanation: As the material is passed only once through the crusher, the excessive formation of undersize product takes place resulting in more energy consumption.




6 - Question

In a closed grinding operation, the material is passed through crusher ____
a) Once
b) After recycle
c) After end
d) Twice

View Answer

Answer: b
Explanation: Material is passed through the crusher several times after each and every product forms, it is send to crusher again to check the completeness of product.




7 - Question

Calculate the operating speed. If the critical speed is 35% of it and 1.05 rps?
a) 3.50
b) 10.6
c) 0.5
d) 0.36

View Answer

Answer: d
Explanation: As operating speed = 35% of Nc = (35/100)*1.05 = 0.36 rps.




8 - Question

Given that R =400 mm and r = 0.03m, what is the critical speed?
a) 0.18
b) 0.81
c) 0.801
d) 8.1

View Answer

Answer: b
Explanation: We know Nc = 1/2π (g/R-r)0.5 = ½*3.14 (9.81/0.4-0.03)0.5 = 0.81 rps.




9 - Question

What will be the angular velocity for a radius of 0.6 m?
a) 40.4 rad/s
b) 10 rad/s
c) 4.04 rad/s
d) 5.6 rad/s

View Answer

Answer: c
Explanation: The angular velocity is wc = (g/r)1/2 = (9.81/0.6)1/2 = 4.04 rad/sec.




10 - Question

If critical speed is 55% more of operating speed and N is 0.81, what is critical speed?
a) 0.26
b) 0.81
c) 0.44
d) 1.25

View Answer

Answer: d
Explanation: As critical = operating + 55% of operating = 0.81 + 55% of 0.81 = 1.25.

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