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Chemical Engineering :: Mechanical Operations

  1. Short distance transportation of grain, gravel, sand, ash, asphalt etc. is done by using a __________ conveyor.

  2. A.
    flight
    B.
    slat or drag
    C.
    ribbon
    D.
    screw

  3. Equivalent diameter of a particle is the diameter of the sphere having the same

  4. A.
    ratio of surface to volume as the actual volume.
    B.
    ratio of volume to surface as the particle.
    C.
    volume as the particle.
    D.
    none of these.

  5. If dp is the equivalent diameter of a non-spherical particle, Vp its volume and sp its surface area, then its sphericity is Φs is defined by

  6. A.
    Φs = 6 Vp/dp sp
    B.
    Φs = Vp/dp sp
    C.
    Φs = 6 dp Sp/Vp
    D.
    Φs = dp Sp/Vp

  7. Power required to drive a ball mill with a particular ball load is proportional to (where, D = diameter of ball mill )

  8. A.
    D
    B.
    1/D
    C.
    D2.5
    D.
    1/D2.5

  9. Pick out the wrong statement.

  10. 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.

  11. In continuous filtration (at a constant pressure drop), filtrate flow rate varies inversely as the

  12. A.
    square root of the velocity.
    B.
    square of the viscosity.
    C.
    filtration time only.
    D.
    washing time only.

  13. For sizing of fine materials, the most suitable equipment is a

  14. A.
    trommel
    B.
    grizzly
    C.
    shaking screen
    D.
    vibrating screen

  15. Which of the following is not categorised as a "mechanical operation" ?

  16. A.
    Agitation
    B.
    Filtration
    C.
    Size enlargement
    D.
    Humidification

  17. Which of the following is a pressure filter ?

  18. A.
    Leaf filter (Moore filter).
    B.
    Plate and flame filter.
    C.
    Rotary drum filter.
    D.
    Sand filter.

  19. Tabular bowl centrifuges as compared to disk bowl centrifuges

  20. A.
    operate at higher speed.
    B.
    employ bowl of larger diameter.
    C.
    can not be operated under pressure/vacuum.
    D.
    can't be used for separation of fine suspended solids from a liquid.