Mechanical Operations Questions and Answers – Advantages of Ball Mill

This set of Mechanical Operations Multiple Choice Questions & Answers (MCQs) focuses on “Advantages Of Ball Mill”.

1. ____ 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. 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. 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.
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4. 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. 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. 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. 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.
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8. 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. 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.
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10. 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.

Sanfoundry Global Education & Learning Series – Mechanical Operations.

To practice all areas of Mechanical Operations, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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Manish Bhojasia - Founder & CTO at Sanfoundry
Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He lives in Bangalore, and focuses on development of Linux Kernel, SAN Technologies, Advanced C, Data Structures & Alogrithms. Stay connected with him at LinkedIn.

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