Mechanical Operations MCQs

Question 1

Which of the following is not used as a filter medium in case of corrosive liquids?

Accepted Answer

Cotton fabric

Answer

Nylon

Answer

Glass cloth

Answer

Metal cloth of monel or stainless steel

Question 2

Which of the following clay mixing devices is vacuum operated for deairation of clay?

Accepted Answer

Pug mill

Answer

Banbery mixer

Answer

Muller-mixer

Answer

None of these

Question 3

For sizing of fine materials, the most suitable equipment is a

Accepted Answer

Vibrating screen

Answer

Trommel

Answer

Grizzly

Answer

Shaking screen

Question 4

For a non-spherical particle, the sphericity

Accepted Answer

Is defined as the ratio of surface area of a sphere having the same volume as the particle to the actual surface area of the particle

Answer

Has the dimension of length

Answer

Is always less than 1

Answer

Is the ratio of volume of a sphere having the same surface area as the particle to the actual volume of the particle

Question 5

A fluid energy mill is used for

Accepted Answer

Ultra grinding

Answer

Cutting

Answer

Grinding

Answer

Crushing

Question 6

Pick out the wrong statement.

Accepted Answer

Capacity of crusher in choke feeding is increased

Answer

Cummulative analysis for determining surface area is preferred over differential analysis, because of the assumption that "all particles in a simple fraction equal in size" is not needed for cummulative anslysis unlike differential anlaysis

Answer

A gate diagram is a plot of cummulative percent by weight undersize vs. the reciprocal of diameter, in which the area beneath the curve represents the surface

Answer

Rolling of pebbles/balls from top to bottom of the heap in tumbling mills is called 'cascading and throwing of the balls through the air to the toe of the heap is called 'cataracting'

Question 7

Theoretical capacity of crushing rolls in tons/hr is given by (where, V = peripherial velocity, m/sec. W = width of rolls, m. Dr = distance between rolls, ρ = density of material to be crushed, kg/m 3 . here V = πN.D, where N = speed of the rolls in rotation per second (rps) D = diameter of rolls, m)

Accepted Answer

3.6 V.W.Dr.ρ

Answer

3.6 V.W.ρ

Answer

3.6 W.Dr.ρ

Answer

3.6 V.W.Dr/ρ

Question 8

In froth floatation, chemical agent added to cause air adherence is called

Accepted Answer

Collector

Answer

Frother

Answer

Modifier

Answer

Activator

Question 9

In filtration, the use of 'filter aid' helps in

Accepted Answer

Deplugging the filter medium

Answer

Reducing the filtration pressure

Answer

Accelerating the rate of filtration

Answer

Enhancing the cake porosity in case of a dense impermeable cake