S7

Question 1

To get ultrafine particles, the equipment used is a

Answer 1

fluid energy mill

Question 1

Vacuum filter is most suitable for the

Answer 1

none of these.

Question 2

The porosity of a compressible cake is

Answer 2

minimum at the filter medium.

Question 3

Which of the following conveyors cannot be recommended for transportation of abrasive materials?

Answer 3

Flight conveyor

Question 4

Separation of materials into products based on the difference of their sizes is called

Answer 4

sizing

Question 5

For classification of potable (drinking) water, we use a __________ filter.

Answer 5

gravity sand

Question 6

Hot, lumpy & abrasive materials are best transported by using a/an __________ conveyor.

Answer 6

apron

Question 7

In case of grinding in a ball mill

Answer 7

all (a), (b) and (c).

Question 8

The capacity of a classifier in ‘tons of solid/hr’ is given by (where, A = cross-sectional area, m2V = rising velocity of fluid, m/sec.S = percentage of solids in the suspension by volume.ρ = density of solids, kg/m3)

Answer 8

3.6 AVS.ρ

Question 9

Kick’s law relates to

Answer 9

energy consumption

Question 10

__________ mill is normally used for grinding of talc.

Answer 10

Ring-roll

Question 11

Colloidal mills are used for __________ grinding.

Answer 11

ultrafine

Question 12

The maximum slope of a belt conveyor can be

Answer 12

30°

Question 13

The filter medium resistance is controlled by

Answer 13

both pressure drop and flow rate

Question 14

The unit of filter medium resistance is

Answer 14

cm^-1

Question 15

During size reduction by a jaw crusher, the energy consumed decreases with the

Answer 15

increasing size of feed at constant reduction ratio.

Question 16

Which of the following can be most effectively used for clarification of lube oil and printing ink?

Answer 16

Sharpies supercentrifuge

Question 17

Ultracentrifuges running at speeds upto 100000 rpm is normally used for the

Answer 17

separation of isotopes based on their density or molecular weights difference.

Question 18

Sizing of very fine particles of the order of 5 to 10 microns is done by elutriation, which is a __________ operation.

Answer 18

classification

Question 19

The basic filtration equation is given asdt/dV = µ/A ∆P (a . CV / A + Rm) where,V is volume of the filtrate ;Ais the filtration area, a is specific cake resistance, μ is viscosity of the filtrate, andC is the concentration of the solids in the feed slurry.

In a 20 minutes constant rate filtration, 5 m3of filtrate was obtained. If this is followed by a constant pressure filtration, how much more time in minutes, it will take for another 5 m3of filtrate to be produced? Neglect filter medium resistance,Rm; assume incompressible cake.

Answer 19

20

Question 20

Size reduction of fibrous materials like wood, asbestos, mica etc. is done by a disintegrator exemplified by the

Answer 20

cage mill

Question 21

The material is crushed in a gyratory crusher by the action of

Answer 21

compression

Question 22

The equivalent diameter of channel of a constant non-circular cross-section of 3 cm by 6 cm will be __________ cms.

Answer 22

2

Question 23

Which of the following may prove unsuitable for filtering volatile liquids?

Answer 23

Vacuum filter

Question 24

__________ mean diameter of particles is given by ∑ (xi / Dpi)

Answer 24

volume

Question 25

Mass flow of granular solid (M) through a circular opening of dia, D follows

Answer 25

M ∝ D^3

Question 26

Sauter mean diameter is the same as the __________ mean diameter.

Answer 26

volume-surface

Question 27

Cake resistance is

Answer 27

none of these.

Question 28

In paint industries, blending of light paste is done by using a

Answer 28

charge can mixer

Question 29

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

Answer 29

0.50

Question 30

__________ is used for producing a thick suspension from a thin slurry.

Answer 30

Pressure filter thickener

Question 31

Wet seiving is employed, when the product contains __________ materials.

Answer 31

large quantity of very fine

Question 32

Energy requirement (per unit mass of material crushed/ground) is highest for

Answer 32

fluid energy mill

Question 33

The energy consumed by a ball mill depends on

Answer 33

all (a), (b) and (c).

Question 34

Energy consumption in a crusher decreases with increase in the

Answer 34

all (a), (b) & (c).

Question 34

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).

Answer 34

Peclet

Question 35

The term 'angle of nip' is concerned with the operation of the __________ crushers.

Answer 35

roll

Question 36

Cartridge filters are termed as 'edge' filters, because of the fact that the

Answer 36

bulk of the solids are removed at the periphery of the disks.

Question 37

Vibrating screens have capacity in the range of __________ tons/ft^2 .mm mesh size.

Answer 37

0.2 to 0.8

Question 38

Cumulative analysis for determining surface is more precise than differential analysis, because of the

Answer 38

assumption that all particles in a single fraction are equal in size, is not needed.

Question 39

To remove very small amount of tiny solid impurities from liquid, we use a

Answer 39

coagulant

Question 40

Screw conveyors are

Answer 40

suitable for sticky materials.

Question 41

__________ mills fall in the category of tumbling mills,

Answer 41

all (a), (b) & (c)

Question 42

Capacity of flight conveyor in tons/hr is given by (where, W & D = width and depth of flight respectively in metre V = speed of the conveyor, metre/second ρ = bulk density of material, kg/m3)

Answer 42

3.6 W.D.V.ρ

Question 43

Which of the following is not a cutting machine?

Answer 43

Tube mills

Question 44

Weber number is significant and is concerned with the

Answer 44

dispersion of liquid in liquid.

Question 45

Power consumption during turbulent flow in agitation tank is proportional to the __________ of the liquid.

Answer 45

density