Mass Transfer

511.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

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512.The unit of volumetric diffusivity is

1. cm²/sec
2. cm/sec
3. cm³/sec
4. cm²/sec2

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513.The value of 'L/mG' ratio for economical absorption operation ranges from

1. 0.5 to 0.8
2. 0.8 to 1.2
3. 1.25 to 2.0
4. 2.5 to 3.5

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514.The value of Lewis number (Le = Sc/Pr) for air-water vapour system is around

1. 1
2. 0.24
3. 3.97
4. 600

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515.The value of N_A/(N_A + N_B) for steady state molecular diffusion of gas 'A' through nondiffusing gas 'B' is

1. 1
2. ∞
3. 0.5
4. 2

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516.The value of N_A/(N_A + N_B), for steady state equimolal counter diffusion of two gases 'A' and 'B' is

1. 1
2. ∞
3. 0.5
4. 2

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517.The vapour pressure exerted by the moisture contained in a wet solid depends upon the

1. Nature of the moisture
2. Temperature
3. Nature of the solid
4. All (A), (B) and (C)

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518.The velocity, concentration and temperature boundary, for the boundary layer development on a flat plate during connective mass transfer will be same, if

1. N_Sc = 1
2. N_Sc = N_Pr = N_Le
3. N_Pr = N_Le
4. N_Sc = N_Le

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519.The wet and 'dry bulb temperature for a vapour-gas mixture are 25°C and 30°C respectively. If the mixture is heated to 45°C at constant pressure, the wet bulb temperature will be _________ °C.

1. 25
2. > 25
3. < 25
4. -25

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520.The wetted wall tower is used to determine

1. Individual mass transfer co-efficient (M.T.C.) in gaseous system
2. M.T.C. of individual components in a liquid-liquid system
3. M.T.C. of liquid in liquid-gas system
4. The overall M.T.C. of the system

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