Related Mcqs:

1. Which of the following equations is Rittinger’s crushing law? (Where P = power required by the machine, m = feed rate, k = a constant, D̅ sa & D̅ sb = volume surface mean diameter of feed & product respectively) ?

   A. P/m = K/ √Dp
   B. P/m = K . ln D̅ sa/D̅ sb
   C. P/m = K . (1/ D̅ sb – 1/D̅ sa)
   D. None of these

2. Sphericity is the ratio of the surface area of a spherical particle having the same volume as the particle to the surface area of the particle. Which of the following has the maximum value of sphericity ?

   A. Sphere
   B. Cube
   C. Cylinder (L/D = 1)
   D. Raschig rings

3. General crushing equation is given by d(P/m) = -K (dD̅ S/D̅ n S). Bond’s crushing law is obtained by solving this equation for n = _____________ and feed of infinite size?

   A. 1
   B. 1.5
   C. 2
   D. 2.5

4. Sphericity for a non-spherical particle is given by (where, V and S are volume and surface area respectively of one particle. and, D = equivalent diameter of particle)?

   A. 6.V/D.S
   B. V/6D.S
   C. D.S/V
   D. V/D.S

5. For crushing of solids, the Rittinger’s law states that the work required for crushing is proportional to __________________?

   A. The new surface created
   B. The size reduction ratio
   C. The change in volume due to crushing
   D. None of these

6. In a size reduction crushing operation, feed size is 300 to 1500 mm while the product size is 100 to 300 mm. This is a case of the ________________ crushing?

   A. Secondary
   B. Fine
   C. Primary
   D. Ultrafine

7. In a size reduction crushing operation, feed size is 100 to 300 mm. while the product size is 10 to 50 mm. This is a case of the _____________ crushing?

   A. Primary
   B. Secondary
   C. Fine
   D. Ultrafine

8. In a size reduction crushing operation, the feed size is 10 to 50 mm, while the product size is 2 to 10 mm. This is a case of _______________ crushing?

   A. Primary
   B. Secondary
   C. Fine
   D. Ultrafine

9. Work index is the gross energy (kWh/tonne of feed) necessary to reduce a very large feed to such a size that 80% of product particles will pass through a 0.1 mm screen. The value of work index determined for wet grinding should be multiplied with ______________ to get the same for dry grinding?

   A. 1.0
   B. 0.5
   C. 1.34
   D. 4.34

10. The constants (Kb, Kr and Kk) used in the laws of crushing (i.e., Bond’s law, Rittinger’s law and Kick’s law) depend upon the_________________?

    A. Feed material
    B. Type of crushing machine
    C. Both A. & B.
    D. Neither A. nor B.