Practice Test: Question Set - 24
1. The grinding in a hammer crusher takes place due to the
- (A) Attrition
- (B) Impact
- (C) Both (a) & (b)
- (D) Neither (a) nor (b)
2. Which of the following can be most effectively used for clarification of lube oil and printing ink?
- (A) Sparkler filter
- (B) Pre-coat filter
- (C) Disc-bowl centrifuge
- (D) Sharpies super-centrifuge
3. The capacity of a belt conveyor depends upon two factors. If one is the cross-section of the load, the other is the __________ of the belt.
- (A) Speed
- (B) Thickness
- (C) Length
- (D) None of these
4. Half the angle of nip, (α), for a roll crusher is given by (where, dr, dp and df are diameters of crushing rolls, feed particles and rolls gap respectively).
- (A) cos α = (dr + dp)/(dr+ df)
- (B) cos α = (dr + df)/(dr+ dp)
- (C) tan α = (dr + dp)/(dr+ df)
- (D) sin α = (dr + dp)/(dr+ df)
5. Size reduction does not occur due to compression in case of
- (A) Rod mills
- (B) Gyratory crushers
- (C) Jaw crushers
- (D) Smooth roll crushers
6. Mixer used for rubber compounding is
- (A) Mixer-extruder
- (B) Banbury internal mixer
- (C) Muller mixer
- (D) Pug mill
7. Mass flow of granular solid (M) through a circular opening of dia, D follows
- (A) M ∝ √D
- (B) M ∝ D2
- (C) M ∝ D3
- (D) M ∝ D
8. Froth floatation is the most suitable for treating
- (A) Iron ores
- (B) Sulphide ores
- (C) Quartzite
- (D) None of these
9. A pebble mill
- (A) Is a ball mill
- (B) Employs flints or ceramic pebbles as the grinding medium
- (C) Is a tube mill lined with ceramic or other non-metallic liner
- (D) Both (b) and (c)
10. Which of the following must be stored in silos and not in open yard?
- (A) Coke breeze
- (B) High V.M. bituminous coal
- (C) Sand
- (D) None of these
11. In a mixer, the quantity, (v. L/D) is termed as __________ number (where, v = longitudinal velocity of material, L = length of the mixer, D = diffusivity in axial mixing).
- (A) Weber
- (B) Peclet
- (C) Brinkman
- (D) Schmidt
12. Sulphuric acid mist is arrested by using a __________ scrubber.
- (A) Packed wet
- (B) Hollow wet
- (C) Venturi
- (D) Co-current
13. In a roll crusher, both the rolls
- (A) Have the same diameter
- (B) Are rotated towards each other
- (C) Run either at the same or different speeds
- (D) All (a), (b) and (c)
14. Addition of filter aid to the slurry before filtration is done to __________ of the cake.
- (A) Increase the porosity
- (B) Increase the compressibility co-efficient
- (C) Decrease the porosity
- (D) Decrease the compressibility co-efficient
15. In froth floatation, chemical agent added to cause air adherence is called
- (A) Collector
- (B) Frother
- (C) Modifier
- (D) Activator
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