A glass contains some water at room temperature 200C. Refrigerated water is added to it slowly. When the temperature of the glass reaches 100 C, small droplets condense on the outer surface. Calculate the relative humidity in the room. The boiling point of water at a pressure of 17.5 mm of mercury is 200 C and at 8.9 mm of mercury it is 100 C.
Given:
SVF at the dew point = 8.9 mm
SVP at room temperature = 17.5 mm
Dew point = 100 C as at this temperature the condensation starts
Room temperature = 200 C
RH=SVP at dew pointSVP at room temp.
= 8.917.5 = 51 %