(a) Evaporation of water
(b) Sublimation of water from ice phase to gas phase
(c) Liquefaction of ice to water
(d) Heating at the freezing temperature of water
16. Dewar flasks are used in
(a) Vacuum drying
(b) Microwave drying
(c) Freeze drying
(d) Rotary drying
17. The most efficient heat exchange between the particles and flowing air occurs in the
(a) Tray dryer
(b) Spray dryer
(c) Fluidized bed dryer
(d) Rotary dryer
18. Following light is mostly used in radiant heat dryer:
(a) Radio waves
(b) Sunlight
(c) UV rays
(d) Infrared rays
19. Reynold’s number (Re) for streamline flow of a fluid is
(a) <0.2
(b) >0.2
(c) <0.8
(d) >0.8
20. Following is not the mechanism of size reduction
(a) Impact and attrition
(b) Cutting
(c) Bruising
(d) Elutriation
21. In dry milling the moisture content should be
(a) <2%
(b) <4%
(c) <6%
(d) <8%
22. For effective operation of ball mill the ball charge
(% volume of mill filled by the balls) should be
(a) 60–70%
(b) 30–50%
(c) <30%
(d) >50%
23. Critical speed of the ball mill is the speed at which
(a) Balls begin to centrifuge with the mill
(b) Balls cascade over one another
(c) Balls are carried up the sides and fall freely onto material
(d) Balls start tumbling
24. Rouwolfia and Glycirriza can be size reduced the best way by of
(a) Roller mill
(b) Ball mill
(c) Cutter mill
(d) Colloid mill
25. Select a mill for a low melting drug.
(a) Hammer mill
(b) Roller mill
(c) Ball mill
(d) Fluid energy mill.
26. According to IP/BP very fine powder is one of which
(a) All particles pass through 120# sieve
(b) 90% particles pass through 350# sieve
(c) All particles pass through 350 # sieve
(d) 90% particles are of size <10μm
27. Total 100 squares in a 1 inch2 area is termed
(a) 100 mesh sieve
(b) 10 mesh sieve
(c) 20 mesh sieve
(d) 25 mesh sieve
28. Following is not a filter aid:
(a) Diatomite
(b) Carbon
(c) Gelatin
(d) Asbestos
29. Filter aids may be applied by
(a) Precoating technique
(b) Body-mix technique
(c) Both
(d) None
30. Integrity tests are intended for following filters:
(a) Leaf filters
(b) Drum filters
(c) Membrane filters
(d) Edge filters
31. The equation describing the factors affecting the rate of filtration is
(a) Darcy’s equation
(b) Dalton’s equation
(c) Stokes’ equation
(d) None
32. For effective screening of all bacteria for sterilization of liquids the membrane pore size is
(a) 0.2μm
(b) 0.45μm
(c) 0.8μm
(d) 1.2μm
33. Duhring’s rule is related to
(a) Crystallization
(b) Distillation
(c) Filtration
(d) Size reduction
34. Filters function by the following mechanism(s)
(a) Sieving or screening
(b) Entrapment or impaction
(c) Electrostatic attraction
(d) All
35. Clarification is the term used when the solid content of the product
(a) Doesn’t exceed 1%
(b) Doesn’t exceed 10%
(c) Doesn’t exceed 5%
(d) All are true
36. Hammer mill works by following principle:
(a) Impact
(b) Attrition
(c) Compression
(d) None
37. Following laws are used to predict energy requirements for comminuting process.
(a) Rittinger’s law
(b) Kick’s law
(c) Bond’s law
(d) All
38. Following is/are dimensionless number(s)
(a) Reynold’s number
(b) Power number
(c) Mass transfer number
(d) All
39. Sweet land filter is a modified type of
(a) Leaf filter
(b) Edge filter
(c) Cartridge filter
(d) Rotary drum filter
40. One of the following mills works on both the principles of inter particulate attrition and impact
(a) Cutter mill
(b) Hammer mill
(c) Roller mill
(d) Fluid energy mill
41. Which one is called as course powder?
(a) All particles must pass through sieve no 10
(b) All particles must pass through sieve no 22
(c) All particles must pass through sieve no 44
(d) All particles must pass through sieve no 85
42. This is the distance between the wires so that it represents the lengths of the sides of square aperture is called
(a) Nominal size of aperture
(b) Nominal diameter of wire
(c) Approximate SCREENING AREA
(d) Aperture tolerance average
43. Which of these is not mechanism of size separation?
(a) Agitation
(b) Brushing
(c) Centrifugation
(d) All of the above
44. Wet sieving method includes...
(a) Sedimentation
(b) Agitation
(c) Centrifugation
(d) All of the above
Answers Keys
15. (b) 16. (c) 17. (c) 18. (d) 19. (a) 20. (d)
21. (a) 22. (b) 23. (a) 24. (c) 25. (d) 26. (a) 27. (b) 28. (c) 29. (c) 30. (c)
31. (c) 32. (a) 33. (b) 34. (d) 35. (a) 36. (a) 37. (d) 38. (d) 39. (a) 40. (d)
41. (a) 42. (a) 43. (d) 44. (a)
