1. What is the relative humidity in a room if the dew point temperature is 41 degrees F and the room temperature is 72 degrees F? (use the attached table to the equation sheet) 2. If a thermodynamic process proceeds isochorically and 200 Joules of heat is added to the system changing its temperature by 20 degrees Celsius, what is the change in internal energy? Solution Relative humidity at a dew point of 41 degree F and room temperature of 72 degree F is 33% (value is calculated with help of standard RH vs dewpoint vs Room temp chart) As the process is isochoric therefore there is no work done involved in the process hence from first law of thermodynamics we can infer that heat given to system is used up in increasing internal energy only. Therefor change in internal energy is +200 Joules .

1. 1. What is the relative humidity in a room if the dew point temperature is 41 degrees F and the
room temperature is 72 degrees F? (use the attached table to the equation sheet)
2. If a thermodynamic process proceeds isochorically and 200 Joules of heat is added to the
system changing its temperature by 20 degrees Celsius, what is the change in internal energy?
305 %
33 %
29 %
37 %
Solution
Relative humidity at a dew point of 41 degree F and room temperature of 72 degree F is 33%
(value is calculated with help of standard RH vs dewpoint vs Room temp chart)
As the process is isochoric therefore there is no work done involved in the process hence from
first law of thermodynamics we can infer that heat given to system is used up in increasing
internal energy only.
Therefor change in internal energy is +200 Joules