Practice Test: Question Set - 17
1. The most efficient equipment for the removal of sub-micronic dust particles from blast furnace gas is the
- (A) Venturi atomiser
- (B) Gravity settling chamber
- (C) Electro-static precipitator
- (D) Cyclone separator
2. Trommels are revolving screens which normally operate in the range of __________ rpm.
- (A) 1 - 2
- (B) 15 - 20
- (C) 40 - 50
- (D) 60 - 75
3. The maximum slope of a belt conveyor can be
- (A) 15°
- (B) 30°
- (C) 45°
- (D) 60°
4. Filter aids like asbestos, kieselguhr, diatomaceous earth etc. are used to increase the porosity of the final filter cake & reducing the cake resistance during filtration. Filter aid is
- (A) Added to the feed slurry
- (B) Pre-coated on the filter medium prior to filtration
- (C) Separated from the cake by dissolving solids or by burning it off
- (D) All 'a', 'b' & 'c'
5. __________ balls capable of grinding the feed in a ball mill gives the maximum efficiency.
- (A) Cast iron
- (B) Minimum size
- (C) Maximum size
- (D) Elliptical
6. Pick out the correct statement.
- (A) Plastic chips are called non-cohesive solids
- (B) Kick's crushing law is, P/m = K . ln (D̅sa/D̅sb)
- (C) Communition is a generic term for size enlargement operation
- (D) Energy required in kwh per ton of product, such that 80% of it passes through a 200 mesh screen, is called 'Work index'
7. A belt conveyor used for the transportation of materials can
- (A) Run upto 1 km
- (B) Travel at a speed upto 300 meters/minute
- (C) Handle materials upto 5000 tons/hr
- (D) All (a), (b) and (c)
8. Ultracentrifuges running at speeds upto 100000 rpm is normally used for the
- (A) Separation of isotopes based on their density or molecular weights difference
- (B) Concentration of rubber latex
- (C) Separation of cream from milk
- (D) Dewaxing of lubricating oil
9. Which of the following is the most suitable for handling fibrous and dense slurries?
- (A) Propeller agitator
- (B) Cone type agitator
- (C) Turbine agitator
- (D) Radial propeller agitator
10. Maximum size reduction in a fluid energy mill is achieved by
- (A) Compression
- (B) Interparticle attrition
- (C) Cutting
- (D) Impact
11. 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
12. Which of the following is not a wet classifier?
- (A) Sharpies super-centrifuge
- (B) Hydrocyclones
- (C) Dorr Oliver rake classifier
- (D) None of these
13. Vibrating screens are used for handling large tonnages of materials. The vibrating motion is imparted to the screening surface by means of
- (A) Electromagnets
- (B) Cams or eccentric shafts
- (C) Unbalanced flywheels
- (D) Either (a), (b) or (c)
14. Size reduction of fibrous materials like wood, asbestos, mica etc. is done by a disintegrator exemplified by the
- (A) Blake jaw crusher
- (B) Cage mill
- (C) Stamp mill
- (D) Bradford's breaker
15. Number of particles in a crushed solid sample is given by (where, m = mass of particles in a sample, Vp = volume of one particle, ρ= density of particles)
- (A) m/ρ . Vp
- (B) m . ρ/Vp
- (C) m . Vp/ρ
- (D) Vp/m . ρ
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