Test: Properties of Moist Air - 3 - Mechanical Engineering MCQ

The barometer pressure is 1.03 bar, the partial pressure of air is 1 bar and the saturation partial pressure of water vapour at the same dry bulb temperature is 0.05 bar. What is the relative humidity?

Air at state 1 (DPT = 10°C, w = 0.0040 kg/kg) mixes with air at state 2 (DPT = 18°C, w = 0.0051 kg/kg) in the ratio 1 to 3 by weight. The degree of saturation (%) of the mixture is (The specific humidity of saturated air at 13.6°C. w = 0.01 kg/kg)

For air with a relative humidity of 80%

For a typical sample of ambient air (at 30°C, 75% relative humidity and standard atmospheric pressure), the amount of moisture in kg per kg of dry air will be approximately

5 gm of water vapour per kg of air is removed and temperature of air after removing water vapour is 25°C DBT.
Find the relative humidity. Use following table,

Air at state 1 (DPT = 1°C, w= 0.0040 kg/kg of da) mixes with air at state 2 (DPT = 18°C, w = 0.0051 kg/kg of da) in the ratio of 1 to 3 by weight the degree of saturation (%) of the mixture is (The specific humidity of saturated air at 13.6°C, w = 0.01 kg/kg of da)

A room 7m x 4m x 4m is occupied by an air- water vapour mixture at 38°C. The atmospheric pressure is 1 bar & relative humidity is 70%. The mass of air is (take P_s at 38°C = 0.06624 bar)