MECHANICAL OPERATIONS QUIZ

Fibrous material is broken by a

Tube mill

Rollcrusher

Squirrel-cage disintegrator

Ball mill

TRUE ANSWER : ?
YOUR ANSWER : ?

Additives used for promoting the floccula-tion of particles is a/an

Surface active agent

Electrolyte

Neither A nor B

Both A & B

TRUE ANSWER : ?
YOUR ANSWER : ?

Rittinger number which designates the new surface prduced per unit of mechanical energy absorbed by the material being crushed, depends on the

Ultimate strength of the material

State or manner of application of the crushing force

All of these

Elastic constant of the material

TRUE ANSWER : ?
YOUR ANSWER : ?

200 mesh seive size corresponds to __________ microns.

154

24

74

200

TRUE ANSWER : ?
YOUR ANSWER : ?

Specific surface area is the surface area of a unit __________ of materials.

Volume

Weight

Neither A nor B

Either A or B

TRUE ANSWER : ?
YOUR ANSWER : ?

Rod mills employed for grinding

Employ steel rods of 2-12 cms diameter extending over full length of the mill

Employ a steel shell having L/D ratio of 1.5 to 3.0

All of these

Is useful for handling sticky materials

TRUE ANSWER : ?
YOUR ANSWER : ?

Cake resistance is

Important in the beginning of filtration

None of these

Decreased with the time of filtration

Independent of pressure drop

TRUE ANSWER : ?
YOUR ANSWER : ?

In case of grinding in a ball mill

Its capacity decreases with increasing fineness of the products

Wet grinding achieves a finer product size than dry grinding

Grinding cost and power requirement increases with increasing fineness of the products

All of these

TRUE ANSWER : ?
YOUR ANSWER : ?

A 30% (by volume) suspension of spherical sand particles in a viscous oil has a hindered settling velocity of 4.44 μm/s. If the Richardson Zaki hindered settling index is 4.5, then the terminal velocity of a sand grain is

0.02 μm/s

22.1 μm/s

1 μm/s

0.90 μm/s

TRUE ANSWER : ?
YOUR ANSWER : ?

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).

Schmidt

Weber

Brinkman

Peclet

TRUE ANSWER : ?
YOUR ANSWER : ?