Mechanical Operations MCQs

Question 1

Sphericity is the ratio of the surface area of a spherical particle having the same volume as the particle to the surface area of the particle. Which of the following has the maximum value of sphericity?

Accepted Answer

Sphere

Answer

Cube

Answer

Cylinder (L/D = 1)

Answer

Raschig rings

Question 2

Maximum size reduction in a fluid energy mill is achieved by

Accepted Answer

Interparticle attrition

Answer

Compression

Answer

Cutting

Answer

Impact

Question 3

Colloidal mills are used for __________ grinding.

Accepted Answer

Ultrafine

Answer

Coarse

Answer

Intermediate

Answer

Fine

Question 4

For separation of sugar solution from settled out mud, we use a __________ filter.

Accepted Answer

Centrifugal

Answer

Sparkler

Answer

Plate and frame

Answer

Rotary drum vaccum

Question 5

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

Accepted Answer

Open sand

Answer

Plate and frame

Answer

Vacuum leaf

Answer

Sparkler

Question 6

Wheat is ground into flour in a

Accepted Answer

Roller crusher

Answer

Hammer crusher

Answer

Impact mill

Answer

Fluid energy mill

Question 7

In coal washeries, three products namely the valuable product (i.e. clean/washed coal), discarded product (i.e. mineral matter) and an additional concentrated product called __________ is produced.

Accepted Answer

Middling

Answer

Concentrate

Answer

Tailing

Answer

None of these

Question 8

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

Accepted Answer

Gravity sand

Answer

Plate and frame

Answer

Vacuum leaf

Answer

Rotary vacuum

Question 9

The critical speed of a trommel (N) is related to its dia (D) as

Accepted Answer

$${	ext{N}} \propto \frac{1}{{\sqrt {	ext{D}} }}$$

Answer

$${	ext{N}} \propto \sqrt {	ext{D}} $$

Answer

$${	ext{N}} \propto {	ext{D}}$$

Answer

$${	ext{N}} \propto \frac{1}{{	ext{D}}}$$