1. ____ is an open container usually cylindrical with uniform openings.

a) Bowel

b) Screen

c) Magnifier

d) Shredder

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2. What is the square opening between screens called?

a) Aperture

b) Abscissa

c) Ordinate

d) Footrope

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3. How is screen effectiveness defined?

a) Maximum*Minimum

b) Retained*Captured

c) Recovery*Rejection

d) Retained* 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

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5. Which of the following resides more energy?

a) Closed Circuit

b) Open circuit

c) Bi-lateral

d) By-pass

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6. In a closed grinding operation, the material is passed through crusher ____

a) Once

b) After recycle

c) After end

d) Twice

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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

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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

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_{c}= 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

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_{c}= (g/r)

^{1/2}= (9.81/0.6)

^{1/2}= 4.04 rad/sec.

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