Practice Test: Question Set - 27
1. Sizing of very fine particles of the order of 5 to 10 microns is done by elutriation, which is a __________ operation.
- (A) Clarification
- (B) Sedimentation
- (C) Flocculation
- (D) Classification
2. Diatomaceous earth is a/an
- (A) Explosive
- (B) Filter aid
- (C) Filter medium
- (D) Catalyst
3. Run of mine (ROM) coal is crushed by a __________ for use in domestic ovens.
- (A) Jaw crusher
- (B) Hammer crusher
- (C) Ball mill
- (D) Tube mill
4. Sedimentation on commercial scale occurs in
- (A) Classifiers
- (B) Thickeners
- (C) Rotary drum filters
- (D) Cyclones
5. A sand mixture was screened through a standard 10-mesh screen. The mass fraction of the oversize material in feed, overflow and underflow were found to be 0.38, 0.79 and 0.22 respectively. The screen effectiveness based on the oversize is
- (A) 0.50
- (B) 0.58
- (C) 0.68
- (D) 0.62
6. Filter aid is used to
- (A) Increase the rate of filtration
- (B) Decrease the pressure drop
- (C) Increase the porosity of the cake
- (D) Act as a support base for the septum
7. __________ conveyor is the most suitable for long distance transportation of cold, non-abrasive granular/irregular shape/fine materials.
- (A) Bucket
- (B) Belt
- (C) Screw
- (D) Apron
8. In a roll crusher, the specific power consumption and the production rate is affected by the
- (A) Reduction ratio
- (B) Differential roll speed
- (C) Both (a) and (b)
- (D) Neither (a) nor (b)
9. __________ mills fall in the category of tumbling mills,
- (A) Ball and pebble
- (B) Rod and tube
- (C) Compartment
- (D) All (a), (b) & (c)
10. The value of 'angle of nip' is generally about
- (A) 16°
- (B) 32°
- (C) 52°
- (D) 64°
11. Pulverized coal passing through 200 mesh screen has a diameter of 0.074 mm (74 micron). The same passing through 50 mesh screen will have a dia of __________ mm.
- (A) 0.007
- (B) 0.30
- (C) 50
- (D) 0.014
12. For Indian standard (IS) screens, the mesh number is equal to its aperture size expressed to the nearest deca-micron (0.01 mm). Aperture width of IS screen of mesh number 50 will be approximately __________ microns.
- (A) 5
- (B) 50
- (C) 500
- (D) 5000
13. For classification of potable (drinking) water, we use a __________ filter.
- (A) Gravity sand
- (B) Plate and frame
- (C) Vacuum leaf
- (D) Rotary vacuum
14. Which of the following is not categorized as a "mechanical operation”?
- (A) Agitation
- (B) Filtration
- (C) Size enlargement
- (D) Humidification
15. Trommels employ __________ for screening of materials.
- (A) Fibrous cloth
- (B) Woven wire screen
- (C) Punched plate
- (D) None of these
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