Pick out the wrong statement ?

Related Mcqs:

1. Pick out the wrong statement ?

   A. Magnetic separation method can be employed to treat both dry & wet ores
   B. Reduction ratio in crushing operation is defined as the ratio of minimum feed size to the
   maximum product size
   C. Gyratory crusher is used for coarse crushing
   D. Screens are of stationary, moving and vibratory types

2. Pick out the wrong statement?

   A. Cumulative 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 cumulative analysis unlike differential analysis
   B. A gate diagram is a plot of cumulative percent by weight undersize vs. the reciprocal of
   diameter, in which the area beneath the curve represents the surface
   C. Capacity of crusher in choke feeding is increased
   D. 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’

3. Pick out the wrong statement ?

   A. More commonly used jaw crusher between Dodge jaw crusher and Blake jaw crusher is the
   later one
   B. There are only four methods namely compression, impact, attrition and cutting, which the size
   reduction equipments employ
   C. Cutting machines mainly employ ‘attrition’ for size reduction of solids
   D. Operating principles of Dodge and Blake jaw crushers are combined in the working of
   universal jaw crushers

4. Pick out the wrong statement pertaining to the turbine agitator ?

   A. Recommended peripheral speed for the turbine agitator is 200-250 metres/minute
   B. Pitched blade turbine agitator gives only radial flow with complete absence of the axial flow
   C. Generally, the diameter of the agitator is kept between l/3rd to l/6th of the tank diameter while
   the blade length is l/4th of agitator diameter (with central disc, it is l/8th of the agitator
   diameter)
   D. Turbine agitator should be located at a height not less than one agitator diameter length from
   the bottom. If the depth of liquid in the tank is more than twice the agitator diameter, two
   agitators should be used

5. Pick out the wrong statement pertaining to the roll crushers?

   A. Maximum feed size determines the required roll diameter
   B. For hard material’s crushing, the reduction ratio should not exceed 4
   C. Both the rolls run necessarily at the same speed
   D. Reduction ratio and differential roll speed affect production rate & energy consumed per unit
   of surface produced

6. Pick out the wrong statement?

   A. Recycled coarse material to the grinder by a classifier is termed as circulating load
   B. Wear and tear in wet crushing is more than that in dry crushing of materials
   C. Size enlargement (opposite of size reduction) is not a mechanical operation
   D. A ‘dust catcher’ is simply an enlargement in a pipeline which permits the solids to settle down
   due to reduction in velocity of the dust laden gas

7. Pick out the wrong statement ?

   A. Gape is the greatest distance between the crushing surfaces or the jaws
   B. The angle of nip (2α) is the angle between roll faces at the level where they will just take hold
   of a particle and draw it in the crushing zone
   C. Crushing efficiency is the ratio of the energy absorbed by the solid to the surfaces energy
   created by crushing
   D. Reduction ratio is the ratio of the maximum size of the particles in the feed to that in the
   product

8. Pick out the wrong statement?

   A. Close circuit grinding is more economical than open circuit grinding
   B. Cod oil, beef tallow or aluminium stearates are used as grinding aids in cement ‘industries’
   C. The equipment used for the removal of traces of solids from a liquid is called a classifier
   D. Size enlargement is a mechanical operation exemplified by medicinal tablet making

9. Pick out the wrong statement ?

   A. Hammer crushers operate by impact action
   B. Standard screens have circular opening
   C. With increase in mesh number of screens, their diameter in microns decreases
   D. 200 mesh screen has 200 openings per linear cm

10. Pick out the correct statement?

    A. The capacity and the effectiveness of a screen are the same
    B. The capacity and the effectiveness of screen are opposing factors
    C. The screening surface of a ‘reel’ (a revolving screen used in flour mills) is made of silk bolting
    cloth supported by wire mesh
    D. Both B. and C.