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  • Question
  • Air initially at 101. 3 kPa and 40°C and with a relative humidity of 50%, is cooled at constant pressure to 30°C. The cooled air has a


  • Options
  • A. higher dew point.
  • B. higher absolute (specific) humidity.
  • C. higher relative humidity
  • D. higher wet bulb temperature.

  • Correct Answer
  • higher relative humidity 


  • Mass Transfer problems


    Search Results


    • 1. Which of the following remains constant during sensible cooling process?

    • Options
    • A. Specific humidity
    • B. Partial pressure of vapour
    • C. Both (a) and (b)
    • D. Neither (a) nor (b)
    • Discuss
    • 2. Total reflux in a distillation operation requires minimum

    • Options
    • A. reboiler load
    • B. number of plates
    • C. condenser load
    • D. all (a), (b) and (c)
    • Discuss
    • 3. As the reflux ratio in a distillation coloumn is increased from the minimum, the

    • Options
    • A. slope of the operating line in stripping section decreases.
    • B. number of plates decreases very slowly first and then more and more rapidly.
    • C. total cost first decreases and then increases.
    • D. liquid flow increases while the vapor flow decreases for a system.
    • Discuss
    • 4. The equipment frequently used for adiabatic humidification-cooling operation with recirculating liquid is

    • Options
    • A. natural draft cooling tower
    • B. induced draft cooling tower
    • C. spray chamber
    • D. none of these
    • Discuss
    • 5. Which of the following unit operations makes use of Thiele-Geddes equation?

    • Options
    • A. Liquid-liquid extraction
    • B. Solid-liquid extraction
    • C. Multicomponent absorption with chemical reaction
    • D. Multicomponent distillation.
    • Discuss
    • 6. Dew point of a gas-vapour mixture

    • Options
    • A. increases with temperature rise.
    • B. decreases with temperature rise.
    • C. decreases with decrease in pressure.
    • D. increases with increase in pressure.
    • Discuss
    • 7. To increase the absorption factor, (where, G = gas flow rate, S = solvent flow rate)

    • Options
    • A. increase both 'G' and 'S'.
    • B. decrease both 'G' and 'S'.
    • C. increase 'S' and decrease 'G'.
    • D. increase 'G' and decrease 'S'
    • Discuss
    • 8. The term "cooling range" in a cooling tower refers to the difference in the temperature of

    • Options
    • A. cold water leaving the tower and the wet bulb temperature of the surrounding air.
    • B. hot water entering the tower and the wet bulb temperature of the surrounding air.
    • C. hot water entering the tower and the cooled water leaving the tower.
    • D. none of these
    • Discuss
    • 9. In distillation columns, the number of bubble caps per tray primarily depends upon the

    • Options
    • A. allowable liquid velocity.
    • B. allowable gas velocity.
    • C. allowable gas and liquid velocities.
    • D. feed composition.
    • Discuss
    • 10. The mass diffusivity, the thermal diffusivity and the eddy momentum diffusivity are same for, NPr = NSc = __________

    • Options
    • A. 1
    • B. 0.5
    • C. 10
    • D. 0
    • Discuss


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