Practice Test: Question Set - 20
1. To remove dirt from the flowing fluid, we use a
- (A) Coagulant
- (B) Gravity settler
- (C) Strains
- (D) Clarifier
2. Pebble mills are tumbling mills widely used for grinding in the manufacture of paints & pigments and cosmetic industries, where iron contamination in the product is highly objectionable. Pebbles used in pebble mill are made of
- (A) Bronze
- (B) Stainless steel
- (C) Flint or porcelain
- (D) Concrete
3. The most suitable equipment used to devulcanise rubber scrap and to make water dispersion & rubber solution is a
- (A) Boundary mixer
- (B) Propeller agitator
- (C) Sharpies centrifuge
- (D) None of these
4. The mechanism of size reduction by a hammer mill is by impact and attrition between the
- (A) Grinding element & the housing
- (B) Feed particles
- (C) Both (a) and (b)
- (D) Neither (a) nor (b)
5. Which of the following may prove unsuitable for filtering volatile liquids?
- (A) Pressure filter
- (B) Gravity filter
- (C) Centrifugal filter
- (D) Vacuum filter
6. Solid particles separation based on the difference in their flow velocities through fluids is termed as the
- (A) Clarification
- (B) Classification
- (C) Elutriation
- (D) Sedimentation
7. A screen is said to be blinded, when the
- (A) Over-sizes are present in undersize fraction
- (B) Under-sizes are retained in oversize fraction
- (C) Screen is plugged with solid particles
- (D) Screen capacity is abruptly increased
8. Size reduction mechanism used in Jaw crushers is
- (A) Attrition
- (B) Compression
- (C) Cutting
- (D) Impact
9. Wet grinding in a revolving mill __________ as compared to dry grinding.
- (A) Gives less wear on chamber walls
- (B) Requires more energy
- (C) Increases capacity
- (D) Complicates handling of the product
10. Wet sieving is employed, when the product contains __________ materials.
- (A) Abrasive
- (B) Large quantity of very fine
- (C) Coarse
- (D) Non-sticky
11. Which of the following is not a part of the Blake jaw crusher?
- (A) Hanger
- (B) Check plates
- (C) Toggles
- (D) Pitman
12. According to Taggart's rule for selecting between a gyratory crusher and a jaw crusher; the later should be used, if the hourly tonnage to be crushed divided by the square of the gape expressed in cm is less than
- (A) 0.00184
- (B) 0.0184
- (C) 0.184
- (D) 1.84
13. Float and sink test determines the possibility of cleaning of coal by a process based on the
- (A) Gravity separation
- (B) Wettability
- (C) Particle shape
- (D) None of these
14. What is the critical rotation speed in revolutions per second, for a ball mill of 1.2 m diameter charged with 70 mm dia balls?
- (A) 0.5
- (B) 1.0
- (C) 2.76
- (D) 0.66
15. Cumulative analysis for determining surface is more precise than differential analysis, because of the
- (A) Assumption that all particles in a single fraction are equal in size
- (B) Fact that screening is more effective
- (C) Assumption that all particles in a single fraction are equal in size, is not needed
- (D) None of these
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