Practice Test: Question Set - 11
1. Pick out the material having minimum Rittinger's number.
- (A) Calcite
- (B) Pyrite
- (C) Quartz
- (D) Galena
2. Sphericity of a cubical particle, when its equivalent diameter is taken as the height of the cube, is
- (A) 0.5
- (B) 1
- (C) √2
- (D) √3
3. About 2-3 hp, power per gallon of a thin liquid provides vigorous agitation in an agitator. 'Power number' in agitation is given by
- (A) P. gc/n3. D2. ρ
- (B) P. gc. ρ/µ2
- (C) n3. D3.
ρ/P.
gc
- (D) P. gc/n2. D2. ρ
4. Gelatinous solid (which plug the septum) can be filtered by a __________ filter.
- (A) Sparkler
- (B) Plate and frame
- (C) Vacuum leaf
- (D) Pre-coat
5. A filter press is
- (A) A batch filter
- (B) Not suitable, if the liquid is the main product
- (C) Having prohibitively high maintenance cost
- (D) Not suitable for wide range of materials under varying operating
conditions of cake thickness and pressure
6. __________ conveyor is the most suitable for short distance transportation of non-abrasive loose materials like garbage, grain, food wastes etc.
- (A) Flight
- (B) Screw
- (C) Drag
- (D) Belt
7. The crushed material received for separation is called feed or
- (A) Tailing
- (B) Heading
- (C) Concentrate
- (D) Middling
8. Sorting classifiers employing differential settling methods for separation of particles make use of the differences in their
- (A) Particle sizes
- (B) Densities
- (C) Terminal velocities
- (D) None of these
9. __________ mill is not a revolving mill.
- (A) Pebble
- (B) Compartment
- (C) Cage
- (D) Tube
10. __________ conveyors are also called scrapers.
- (A) Apron
- (B) Screw
- (C) Helical flight
- (D) Both (b) & (c)
11. Which of the following equations is Rittinger's crushing law? (Where P = power required by the machine, m = feed rate, k = a constant, D̅sa & D̅sb = volume surface mean diameter of feed & product respectively.)
- (A) P/m = K/ √Dp
- (B) P/m = K .
ln D̅sa/D̅sb
- (C) P/m = K .
(1/ D̅sb - 1/D̅sa)
- (D) None of these
12. Fibrous material is broken by a
- (A) Roll-crusher
- (B) Squirrel-cage disintegrator
- (C) Ball mill
- (D) Tube mill
13. For coarse reduction of hard solids, use
- (A) Impact
- (B) Attrition
- (C) Compression
- (D) Cutting
14. Work index is defined as the
- (A) Gross energy (kWh/ton of feed) needed to reduce very large feed to
such a size that 80% of the product passes through a 100 micron screen
- (B) Energy needed to crush one tonne of feed to 200 microns
- (C) Energy (kWh/ton of feed) needed to crush small feed to such a size
that 80% of the product passes a 200 mesh screen
- (D) Energy needed to crush one ton of feed to 100 microns
15. __________ mills are termed as impactors.
- (A) Hammer
- (B) Cage
- (C) Rolling-compression
- (D) None of these
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