## Lakshya Education MCQs

Question: __________ number indicates the ratio of the rates of the heat and mass transfer incase of a cooling tower.
Options:
 A. Sherwood B. Stanton C. Lewis D. Peclet

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## More Questions on This Topic :

Question 1. Pick out the wrong statement.
1.    In the McCabe-Thiele diagram for binary distillation, vertical feed line represents saturated liquid feed and horizontal feed line represents saturated vapour feed
2.    In small columns, local efficiency is larger than Murphree efficiency; in large columns local efficiency is smaller than Murphree efficiency
3.    For Laminar flow over a plate of length L, the local mass transfer co-efficient at a distance L from the leading edge is 1.5 x 10⁻²m/s. Then the average mass transfer co-efficient for the plate is
4.    The concentration and hydrodynamic boundary layers over a flat plate are of equal thickness, if Schmidt number is equal to unity
Question 2. The term "cooling range" in a cooling tower refers to the difference in the temperature of
1.    Cold water leaving the tower and the wet bulb temperature of the surrounding air
2.    Hot water entering the tower and the wet bulb temperature of the surrounding air
3.    Hot water entering the tower and the cooled water leaving the tower
4.    None of these
Question 3. Batch tray dryers suffers from the disadvantage of
1.    High maintenance cost
2.    Non-uniform & low production rate
3.    High labour cost & low heat economy
4.    All of the above
Question 4. Mass transfer co-efficient is defined as
1.    Flux = Co-efficient/concentration difference
2.    Co-efficient = Flux/concentration difference
3.    Flux=concentration difference/co-effi-cient
4.    None of these
Question 5. Fenske equation determines the
1.    Maximum number of ideal plates
2.    Height of the distillation column
3.    Minimum number of theoretical plates
4.    Optimum reflux ratio