Mechanical Operations - Practice Test

[#286] The porosity of a compressible cake is

(A) Minimum at the filter medium

(B) Minimum at the upstream face

(C) Maximum at the filter medium

(D) Same throughout the thickness of cake

Correct Answer

(A) Minimum at the filter medium

[#287] Arrange the following size reduction equipment in the decreasing order of the average particle size produced by each of them.

(A) Jaw crusher, Ball mill, Fluid energy mill

(B) Ball mill, Jaw crusher, Fluid energy mill

(C) Fluid energy mill, Jaw crusher, Ball mill

(D) Fluid energy mill, Ball mill, Jaw crusher

Correct Answer

(A) Jaw crusher, Ball mill, Fluid energy mill

[#288] If D p is the equivalent diameter of a non-spherical particle, V p its volume and S p its surface area, then its sphericity is Φ s is defined by

(A) Φ s $$ = frac{{6{{ ext{V}}_{ ext{p}}}}}{{{{ ext{D}}_{ ext{p}}}{{ ext{S}}_{ ext{p}}}}}$$

(B) Φ s $$ = frac{{{{ ext{V}}_{ ext{p}}}}}{{{{ ext{D}}_{ ext{p}}}{{ ext{S}}_{ ext{p}}}}}$$

(C) Φ s $$ = frac{{6{{ ext{D}}_{ ext{p}}}{{ ext{S}}_{ ext{p}}}}}{{{{ ext{V}}_{ ext{p}}}}}$$

(D) Φ s $$ = frac{{{{ ext{D}}_{ ext{p}}}{{ ext{S}}_{ ext{p}}}}}{{{{ ext{V}}_{ ext{p}}}}}$$

Correct Answer

(A) Φ s $$ = frac{{6{{ ext{V}}_{ ext{p}}}}}{{{{ ext{D}}_{ ext{p}}}{{ ext{S}}_{ ext{p}}}}}$$

[#289] __________ is the most commonly used 'filter aid'.

(A) Diatomaceous earth

(B) Fuller's earth

(C) Vermiculite

(D) Semi-plastic clay

Correct Answer

(A) Diatomaceous earth

[#290] All resistances during washing of cake

(A) Increases

(B) Decreases

(C) Remain constant

(D) None of these

(E) Increases

(F) Decreases

(G) Remain constant

(H) None of these

Correct Answer

(C) Remain constant
(G) Remain constant

Mechanical Operations - Study Mode

[#286] The porosity of a compressible cake is

Correct Answer

[#287] Arrange the following size reduction equipment in the decreasing order of the average particle size produced by each of them.

Correct Answer

[#288] If D p is the equivalent diameter of a non-spherical particle, V p its volume and S p its surface area, then its sphericity is Φ s is defined by

Correct Answer

[#289] __________ is the most commonly used 'filter aid'.

Correct Answer

[#290] All resistances during washing of cake

Correct Answer