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Chemical Engineering :: Heat Transfer

  1. Which of the following is correct ?

  2. A.
    Rate = Driving force x Resistance
    B.
    Driving force = Rate x Resistance
    C.
    Resistance = Driving force x Rate
    D.
    Rate = Resistance/Driving force

  3. Convective heat transfer, in which heat is transferred by movement of warmed matter is described by

  4. A.
    Fourier's law
    B.
    Newton's law of cooling
    C.
    Fick's law
    D.
    none of these

  5. As the difference between the wall temperature and bulk temperature increases, the boiling heat transfer co-efficient

  6. A.
    continues to increase.
    B.
    continues to decrease.
    C.
    goes through a minimum.
    D.
    goes through a maximum.

  7. Heat transfer rate per unit area is called

  8. A.
    thermal conductivity
    B.
    heat flux
    C.
    heat transfer co-efficient
    D.
    thermal diffusivity

  9. Log mean temperature difference (LMTD) cannot be used, if

  10. A.
    heat transfer co-efficient over the entire heat exchanger is not constant.
    B.
    there exists an unsteady state.
    C.
    the heat capacity is not constant and there is a phase change.
    D.
    none of these.

  11. In a multipass shell and tube heat exchanger, tube side return pressure loss is equal to __________ the velocity head.

  12. A.
    twice
    B.
    four times
    C.
    square root of
    D.
    square of

  13. For a given ambient air temperature with increase in the thickness of insulation of a hot cylinderical pipe, the rate of heat loss from the surface would

  14. A.
    decrease
    B.
    increase
    C.
    first decrease and then increase
    D.
    first increase and then decrease

  15. In a parallel flow heat exchanger, if the outlet temperature of hot and cold fluids are the same, then the log mean temperature difference (LMTD) is

  16. A.
    minimum
    B.
    maximum
    C.
    zero
    D.
    infinity

  17. For what value of Prandtl number, the Col-burn analogy is valid ?

  18. A.
    0.06 to 120
    B.
    0.6 to 120
    C.
    1 to 103
    D.
    l to 50

  19. In a forward feed multiple effect, the pressure build up will be

  20. A.
    least at the inlet of the first effect.
    B.
    least at the outlet of the last effect.
    C.
    highest at the inlet of the last effect.
    D.
    highest at the outlet of the last effect.