An air-water vapour mixture has a dry bulb temperature of 60°C and a dew point temperature of 40°C. The total pressure is 101.3 kPa and the vapour pressure of water at 40°C and 60°C are 7.30 kPa and 19.91 kPa respectively. The humidity of air sample expressed as kg of water vapour/kg of dry air is__________________?

Related Mcqs:

1. At equilibrium the concentration of water in vapour phase (C*) in kg/m3 of air space and the amount of water (m) adsorbed per kg of dry silica gel are related by, C* = 0.0667m. To maintain dry conditions in a room of air space 100m3 containing 2.2 kg of water vapour initially, 10 kg of dry silica gel is kept in the room. The fraction of initial water remaining in the air space after a long time (during which the temperature is maintained constant) is_________________?

   A. 0.0
   B. 0.2
   C. 0.4
   D. 1.0

2. Humidity chart is useful for the solution of problems concerning condensation, vaporisation and air conditioning. At a given dry bulb temperature, value of humidity obtained from the humidity chart directly, is in terms of _______________ humidity?

   A. Molal
   B. Relative
   C. Percentage
   D. None of these

3. Humidity chart is useful for the solution of problems concerning condensation, vaporisation and air conditioning. At a given dry bulb temperature, value of humidity obtained from the humidity chart directly, is in terms of _______________ humidity?

   A. Molal
   B. Relative
   C. Percentage
   D. None of these

4. 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 ?

   A. 25
   B. > 25
   C. < 25
   D. – 25

5. 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?

   A. 25
   B. > 25
   C. < 25
   D. – 25

6. 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____________________?

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

7. Unsaturated air (with dry bulb temperature and dew point being 35°C and 18°C respectively) is passed through a water spray chamber maintained at 15°C. The air will be cooled_________________?

   A. And humidified
   B. And dehumidified with increase in wet bulb temperature
   C. At the same relative humidity
   D. And dehumidified with decrease in wet bulb temperature

8. Which of the following processes is followed by unsaturated air (with dry bulb temperature 12°C and relative humidity 47%) passing through water spray washer (temperature of water being constant at 40°C ?

   A. Humidification only
   B. Heating only
   C. Both heating and humidification
   D. Evaporative cooling

9. Unsaturated air (with dry bulb and wet bulb temperatures being 45°C and 25°C respectively) is passed through a water spray chamber maintained at 23°C. The air will be cooled and _________________?

   A. Humidified with wet bulb temperature decreasing
   B. Humidified at constant wet bulb temperature
   C. Dehumidified
   D. None of these

10. Which of the following can be calculated theoretically using steam table and Dalton’s law of partial pressure; if the relative humidity and dry bulb temperature of moist air is known ?

    A. Dew point
    B. Humidity ratio
    C. Wet bulb temperature
    D. None of these