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Chemical Engineering :: Mechanical Operations

  1. For a turbine agitated and baffled tank, operating at low Reynold's number (based on impeller diameter), the power number (Np) varies with NRe as

  2. A.
    NpNRe
    B.
    NpNRe
    C.
    Np → constant
    D.
    Np ∝ 1/NRe

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  3. Which of the following is not accomplished by agitation of liquids in agitators?

  4. A.
    Dispersing gas in liquid.
    B.
    Blending of immiscible liquids.
    C.
    Dispersing immiscible liquid in form of emulsion.
    D.
    Suspending solid particles.

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  5. Which of the following parts of a jaw crusher is subjected to maximum wear and tear during its operation ?

  6. A.
    Check plates
    B.
    Jaw plates
    C.
    Toggles
    D.
    Crush shaft

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  7. A 30% (by volume) suspension of spherical sand particles in a viscous oil has a hindered settling velocity of 4.44 μm/s. If the Richardson Zaki hindered settling index is 4.5, then the terminal velocity of a sand grain is

  8. A.
    0.90 μm/s
    B.
    1 μm/s
    C.
    22.1 μm/s
    D.
    0.02 μm/s

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  9. The specific surface of spherical particles is given by (where D and ρ are diameter and density of particle).

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  11. 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)

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  13. In froth floatation, chemical agent added to cause air adherence is called

  14. A.
    collector
    B.
    frother
    C.
    modifier
    D.
    activator

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  15. The sphericity of a solid particle of cubical shape is

  16. A.
    π
    B.
    (π/6)1/3
    C.
    (π/6)1/2
    D.
    π/3

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  17. Vertical transportation of materials can be done by a/an

  18. A.
    apron conveyor
    B.
    pneumatic conveyor
    C.
    bucket elevator
    D.
    both(b)&(c)

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  19. In a roll crusher, the specific power consumption and the production rate is affected by the

  20. A.
    reduction ratio.
    B.
    differential roll speed.
    C.
    both (a) and (b).
    D.
    neither (a) nor (b).

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