S2

Question 1

Energy consumed for crushing one ton of material ranges from __________ kWh.

Answer 1

0.5 to 1.5

Question 2

For transporting pasty material, one will use a/an

Answer 2

screw colaveyor

Question 3

Where the density difference of the two liquid phase to be separated is very small (as in milk cream separator), the most suitable separator is a

Answer 3

disc bowl centrifuge.

Question 4

A tube mill compared to a ball mill

Answer 4

has a higher length/diameter ratio.

Question 5

Trommels separate a mixture of particles depending on their

Answer 5

size

Question 6

Basic slag is not ground in

Answer 6

jaw crushers

Question 7

Grindability of a material does not depend upon its

Answer 7

size

Question 8

Shape factor for a cylinder whose length equals its diameter is

Answer 8

1.5

Question 9

In case of a hammer crusher, the

Answer 9

rotor shaft carrying hammers can be vertical or horizontal.

Question 10

Dust laden air can be purified using a

Answer 10

cyclone separator

Question 11

Rittinger’s number designates the new surface created per unit mechanical energy absorbed by the material being crushed. Larger value of Rittinger’s number of a material indicates its

Answer 11

easier grindability

Question 12

Capacity (in tons/hr) of jaw/gyratory crusher is equal to (where,L= length of the receiving opening, cmS= greater width of the discharge opening, cm)

Answer 12

0.087L.S

Question 13

Vacuum is applied in __________ zone, in case of a general type continuous rotary drum vacuum filter.

Answer 13

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

Question 14

General crushing equation is given by d(rho/m) = - K d Ds / Dns. Bond’s crushing law isobtained by solving this equation for n = __________ and feed of infinite size.

Answer 14

1.5

Question 15

Which of the follwoing mechanical conveyors does not come under the division ‘scrapers’?

Answer 15

Bucket elevators

Question 16

__________ mixer is used for devulcanisation of rubber scrap & making water dispersion & rubber solution.

Answer 16

Banbery

Question 17

Which of the following mechanical conveyors does not come under the division ‘carriers’?

Answer 17

Screw conveyor

Question 18

Screen capacity is not a function of

Answer 18

atmospheric humidity.

Question 19

Which of the following is a vacuum filter?

Answer 19

Rotary disc filter

Question 20

Pine oil used in froth floatation technique acts as a/an

Answer 20

frother

Question 21

Length/diameter ratio of a ball mill is

Answer 21

< 1

Question 22

Feed size of ≥ 25 cms can be accepted by

Answer 22

jaw crusher

Question 23

Which is the most suitable conveyor for transportation of sticky material?

Answer 23

Screw conveyor

Question 24

The most suitable equipment for removing the fine dust particle (< 1 micron dia.) from air below its dew point will be a/an

Answer 24

electrostatic precipitator

Question 25

Laminar flow region is said to exist during agitation of a liquid in an agitator, when the value of Reynolds number is

Answer 25

<10

Question 26

Sphericity of a cubical particle, when its equivalent diameter is taken as the height of the cube, is

Answer 26

1

Question 27

Filtration of water in a paper mill is done by a/an __________ filter.

Answer 27

open sand

Question 27

Moore filter is a __________ filter.

Answer 27

leaf

Question 28

Ball mill is used for

Answer 28

fine grinding

Question 29

In case of a ball mill,

Answer 29

coarse feed requires a larger ball.

Question 30

Maximum size reduction in a ball mill is done by the, __________ action.

Answer 30

impact

Question 31

increasing the capacity of a screen __________ the screen effectiveness.

Answer 31

decreases.

Question 32

The power number for a stirred tank becomes constant at high Reynolds number. In this limit, the variation of power input with impeller rotational speed (N) is proportional to

Answer 32

N2

Question 33

Bond crushing law

Answer 33

calls for relatively less energy for the smaller product particles, than does the Rittinger law.

Question 34

Flow of filtrate through the cake in a plate and frame filter press is best described by the __________ equation.

Answer 34

Kozney-Karman

Question 35

The controlling resistance in a rotary drum vacuum filter is the __________ resistance.

Answer 35

cake

Question 36

Which of the following is used for primary crushing of very hard lumpy materials?

Answer 36

Gyratory crusher

Question 37

Coal is finally pulverised to 200 mesh size for burning in boilers by a

Answer 37

ball mill

Question 38

Crushing efficiency is the ratio of the

Answer 38

surface energy created by crushing to the energy absorbed by the solid.

Question 39

The resistance offered by the filter used in a bag filter is proportional to (where, c = dust concentration, and s = particle size)

Answer 39

c/s

Question 40

Cement clinker is reduced to fine size by a

Answer 40

tube mill

Question 41

The crushed material received for separation is called feed or

Answer 41

heading

Question 42

For spheres, volume shape factor is given by

Answer 42

π/6(=V/D3)

Question 43

Which of the following agitators having a large blade area, rotating at slow speed is used for mixing high viscosity liquids ( > 50000 centipoise)?

Answer 43

Helical screw

Question 44

__________ is defined as the geometric mean of the relative rejections and the relative recoveries of two minerals.

Answer 44

Selectivity index

Question 45

The operating speed of a ball mill should be __________ the critical speed.

Answer 45

less than

Question 46

__________ are used for the separation of coarse particles from a slurry of fine particles.

Answer 46

Classifiers

Question 47

Fibrous material is broken by a

Answer 47

squirrel-cage disintegrator

Question 48

__________ is the most suitable for compounding rubber and plastic solids.

Answer 48

Banbery mixer