1. According to Rittingers law, work required is proportional to _________
a) Energy Consumed
b) Surface area created
c) Final Volume
d) Initial feed
Explanation: The Rittingers law states that “The work required in crushing is directly proportional to the new surface area created”.
2. Following Rittingers law, Crushing efficiency is ____
a) Independent of feed material
b) Independent of size of feed and product
c) Independent of energy consumed
d) Independent of area
Explanation: Crushing efficiency is constant and for a given machine and feed material, is independent of size of feed and product.
3. On which of the given, Kick’s law is based?
a) Cumulative analysis
b) Frequency analysis
c) Stress analysis
d) Screen analysis
Explanation: Kick proposed another law, based on the stress analysis of plastic deformation within the elastic limits.
4. The ratio of initial particle size to final particle size is defined as _____
a) Reduction ratio
b) Kick’s ratio
c) Rittingers ratio
d) Bond’s ratio
Explanation: The reduction ratio for a crusher is defined as the ratio of feed opening to the discharge opening i.e. Dsa/Dab.
5. Kick’s law holds well for ____
a) Fine crushing
b) Simple crushing
c) Full crushing
d) Coarse crushing
Explanation: Kick’s law holds good for coarse crushing and amount of surface produced is less.
6. On which of the following, Kf and Kk depends?
a) Type of machine
b) Type of power
c) Type of operation
d) Type of law
Explanation: Both Kick’s and Rittingers law is applied over a limited range of the particles size, hence Kf and Kk depend upon type of machine.
7. The most accurate law for estimating the power is ____
a) Rittingers law
b) Bond’s law
c) Kick’s law
d) Power law
Explanation: Bond’s law is more realistic for estimating the power required for the crushing and grinding operations of any kind.
8. What is the surface to volume ratio?
a) Sp/Dp
b) Sp/Vp
c) Dp/Vp
d) Dp/Kp
Explanation: The surface to volume ratio is given as Sp/Vp, where Sp is surface area and Vp is the volume of the feed.
9. On which of the following, Kb depends?
a) Type of machine and material
b) Type of power
c) Type of operation
d) Type of law
Explanation: According to Bond’s law, the Bond’s constant Kb depends upon the type of machinery used and the type of feed applied.
10. The gross energy requirement is called as ____
a) Work index
b) Power index
c) Energy index
d) Final index
Explanation: Work index is defined as the gross energy requirement in kilowatt hours per unit ton of feed needed to reduce very large feed to 80%.