me op 4 Flashcards
_____ mills fall in the category of tumbling mills,
A. Ball and pebble
B. Rod and tube
C. Compartment
D. All
D
Which of the following is not a cutting machine?
A. Dicers
B. Knife cutters
C. Slitters
D. Tube mills
D
Weber number is significant and is concerned with the
A. solid-liquid mixing
B. liquid-liquid mixing
C. dispersion of liquid in liquid
D. suspension of solid in liquid
C
Power consumption during turbulent flow in agitation tank is
proportional to the _______ of the liquid.
A. viscosity
B. thermal conductivity
C. surface tension
D. density
D
Screen efficiency is
A. recovery/rejection
B. recovery
C. rejection
D. none of these
D
Handling of ashes and similar materials can be done best by a
______ conveyor.
A. flight
B. drag or slat
C. belt
D. ribbon
B
200 mesh sieve size corresponds to ____ microns.
A. 24
B. 74
C. 154
D. 200
B
Which of the following must be stored in silos and not in open
yard?
A. Coke breeze
B. High V.M. bituminous coal
C. Sand
D. None of these
B
Apron conveyors are used for
A. heavy loads & short runs
B. small loads & long runs
C. heavy loads & long runs
D. none of these
A
Sedimentation on commercial scale occurs in
A. classifiers
B. thickeners
C. rotary drum filters
D. cyclones
C
With increase in drum speed, in a rotary drum filter, the filtration
rate
A. increases
B. increases linearly
C. decreases
D. is not affected
A
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
A
Capacity of flight conveyor in tons/hr is given by (where, W & D
= width and depth of flight respectively in metre V = speed of the
conveyor, meter/second 𝜌 = bulk density of material, kg/m3)
A. 3.6 W.D.V. ρ
B. 3.6 W.D.V.
C. 3.6 W.V. ρ
D. 3.6 D.V. 𝜌
A
What is the usual value of angle of nip for crushing of ordinary
rock in smooth steel crushing rolls?
A. 16°
B. 32°
C. 40°
D. 46°
B
For grinding of cereals, grains, spices, pigments, saw dust, cork,
etc., the most extensively used size reduction equipment is a
A. Buhrstone mill
B. ball mill
C. crushing rolls
D. hammer mill
A
For a turbine agitated and baffled tank, operating at low
Reynold’s number (based on impeller diameter), the power
number (𝑁) varies with 𝑁 as
A. 𝑁p ∝𝑁re
B. 𝑁p ∝ sqrt(𝑁re)
C. 𝑁p→𝑐𝑜𝑛𝑠𝑡𝑎𝑛𝑡
D. Np ∝1/Nre
D
Which of the following is not accomplished by agitation of liquids
in agitators?
A. Dispersing gas in liquid.
B. Blending of immiscible liquids.
C. Dispersing immiscible liquids in form of emulsion.
D. Suspending solid particles.
B
Which of the following parts of a jaw crusher is subjected to
maximum wear and tear during its operation?
A. Check plates
B. Jaw plates
C. Toggles
D. Crush shaft
B
A 30% (by volume) suspension of spherical sand particles in a
viscous oil has a hindered settling velocity of 4.44 um/s. if the
Richardson Zaki hindered settling index is 4.5, then the terminal
velocity of a sand grain is
A. 0.90 um/s
B. 1 um/s
C. 22.1 um/s
D. 0.02 um/s
B
The specific surface of spherical particles is given by (where D
and ρ are diameter and density of particle).
A. 6/D p
B. 2/D p
C. 4/D p
D. 12/D p
A
Velocity of a small particle of diameter ‘DP’ at a distance ‘r’ from
the rotational axis of a cyclone rotating at an angular speed ‘𝜔’
is given by (the other symbols are as per standard notation)
A. (Dp/18 - ps-p/u) 𝜔^2𝑟
B. (Dp^2/18 - ps-p/u)𝜔𝑟^2
C. (Dp/18 - ps-p/u) 𝜔^2𝑟^2
D. (Dp^2/18 - ps-p/u)𝜔^2𝑟
D
In froth flotation, chemical agent added to cause air adherence
is called
A. collector
B. frother
C. modifier
D. activator
A
The sphericity of a solid particle of cubical shape is
A. 𝜋
B. (𝜋/6)^1/3
C. (𝜋/6)^1/2
D. 𝜋/3
B
Vertical transportation of materials can be done by a/an
A. apron conveyor
B. pneumatic conveyor
C. bucket elevator
D. both b & c
D