Practice Pakistan's most useful MCQs for competitive exams

In a size reduction crushing operation, the feed size is 10 to 50 mm, while the product size is 2 to 10 mm. This is a case of _______________ crushing?

• (A)  Primary
• (B)  Secondary
• (C)  Fine
• (D)  Ultrafine

Answer

Submitted By :Ali Uppal

Theoretical capacity of crushing rolls in tons/hr is given by (where, V = peripheral velocity, m/sec. W = width of rolls, m Dr = distance between rolls ρ = density of material to be crushed, kg/m3 here, V =πND where, N = speed of the rolls in rotation per second (rps) D = diameter of rolls, m) ?

• (A)  3.6 V.W.Dr.ρ
• (B)  3.6 V.W. ρ
• (C)  3.6 W.Dr.ρ
• (D)  3.6 V.W.Dr/ρ

Answer

Submitted By :Ali Uppal

Separation of particles of various sizes, shapes and densities by allowing them to settle in a fluid is called__________________?

• (A)  Classification
• (B)  Froth floatation
• (C)  Thickening
• (D)  Clarification

Answer

Submitted By :Ali Uppal

The controlling resistance in a rotary drum vacuum filter is the ________________ resistance?

• (A)  Piping
• (B)  Cake
• (C)  Filter medium
• (D)  None of these

Answer

Submitted By :Ali Uppal

To get a fine talc powder from its granules, the equipment used is____________________?

• (A)  Roller crusher
• (B)  Ball mill
• (C)  Jaw crusher
• (D)  Gyratory crusher

Answer

Submitted By :Ali Uppal

In classification, particles are said to be equal settling, if they have the same terminal velocities in the_______________?

• (A)  Different fluids
• (B)  Same fluid
• (C)  Same field of force
• (D)  Both

Answer

Submitted By :Ali Uppal

Introduction of slurry in a plate and frame filter press is done through a plate in each frame. The plate of this filter has a _______________ surface?

• (A)  Plane
• (B)  Curved
• (C)  Ribbed
• (D)  Either

Answer

Submitted By :Ali Uppal

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

• (A)  Banbury mixer
• (B)  Pug mill
• (C)  Muller-mixer
• (D)  None of these

Answer

Submitted By :Ali Uppal

With increase in the pressure drop across the cake, the specific cake resistance for the compressible sludge________________?

• (A)  Increases
• (B)  Decreases
• (C)  Remains constant
• (D)  Increases linearly

Answer

Submitted By :Ali Uppal

There is practically no alternative/competitor to _________________ in the beneficiation treatment of sulphide ores?

• (A)  Classification
• (B)  Tabling
• (C)  Jigging
• (D)  Froth floatation

Answer

Submitted By :Ali Uppal