Which of the following achieves the least reduction ratio for a given feed size ?

Related Mcqs:

1. According to Bond crushing law, the work required to form particle of size ‘D’ from very large feed is (where (S/V)p and (S/V)f are surface to volume ratio of the product and feed respectively) ?

   A. (S/V)p
   B. √(S/V)p
   C. (S/V)2p
   D. (S/V)f

2. What is the reduction ratio in a fine crushing operation having following feed and product sizes ?

   A. 0.5
   B. 2
   C. 5
   D. 10

3. The reduction ratio for grinders is defined as (where, Df and Dp are average diameters of feed and product respectively) ?

   A. Df/Dp
   B. Dp/Df
   C. Df – Dp
   D. None of these

4. 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

5. 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

6. Out of the following size reduction equipments, the maximum feed size can be accepted by the__________________?

   A. Tube mill
   B. Ball mill
   C. Jaw crusher
   D. Jet pulveriser

7. 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

8. 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

9. 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

10. Half the angle of nip, (α), for a roll crusher is given by (where, dr, dp and df are diameters of crushing rolls, feed particles and rolls gap respectively) ?

    A. cos α = (dr + dp)/(dr + df)
    B. cos α = (dr + df)/(dr + dp)
    C. tan α = (dr + dp)/(dr + df)
    D. sin α = (dr + dp)/(dr + df)