1. Heavy particles have relatively faster velocity that light particles.
Answer: a [Reason:] As the heavier particle are having more weight the more tendency to get down to the bottom of the settling tank as compared to light particles.
2. A material has an initial acceleration of _____
b) g [1- p/Pa]
c) g [Pa/p]
Answer: b [Reason:] A particle of material ‘A’ will have an initial acceleration of g [1- p/Pa], because there is no fluid friction and only depends on density.
3. If width resembles the capacity, then length resembles ___
Answer: b [Reason:] The width gives us the idea about the capacity how much a screen can hold whereas the length makes a guess of the efficiency the longer the path the better it is.
4. Which of the following can be used for separation of pulp?
b) Drag classifier
c) Liquid cyclone
d) Cone classifiers
Answer: d [Reason:] The cone classifiers are not suitable for pulp having a tendency to build mud banks, it requires more operating attention than mechanical classifiers.
5. While screening, the material which is left on the screen is called as ____
Answer: a [Reason:] The material retained on the screen is called as overflow or undersized as they did not pass through the screen size of that particular equipment.
6. Drag classifiers sizes up to ___
a) 10*41 ft2
b) 20*81 ft2
c) 50*74 ft2
d) 11*21 ft2
Answer: a [Reason:] Modern design and materials of construction permits sizes up to 10 ft. wide and 41 ft. long on steeper than average slopes and very high tonnage.
7. Which is best of the following for fine separation?
a) Tumbler mill
b) Drag classifier
c) Rake classifier
d) Dorr classifier
Answer: c [Reason:] Separations as fine as up to 325 mesh can be accomplished at reduced tonnage rates, they are generally used for closed circuit grinding.
8. For a bowl desiltor, discharge is settled at ___
Answer: b [Reason:] In a bowl desiltor, the rotating blades in the bowl plow outward and settled coarse material at the peripheral outlet.
9. The solid bowl classifier uses principle of ___
a) Raw force
b) Gravitational force
c) Centrifugal force
d) Kinetic energy
Answer: c [Reason:] Solid bowl classifier or centrifuge uses centrifugal force, it can develop centrifugal forces up to 1800 times the force of gravity.
10. What is FR?
a) Kinematic force
b) Drag force
c) Fumble force
d) Resistance force
Answer: a [Reason:] The kinematic force FR can be expressed as FR = AKf, where A is the area of the system and f is the dimensionless parameter and K is kinetic energy.