# Homework Help: Psychrometrics: Dew-point temp from Relative Humidity

1. Mar 31, 2012

### mojomike

1. The problem statement, all variables and given/known data

Air/Water vapor mixture, at 26C and 45%RH.
What is the Dew-point temperature

2. Relevant equations

Tdp = Tsat when pg=pv
RH = pv/pg

3. The attempt at a solution

From the psychrometric chart I can get the Humidity ratio, volume per kg dry air, Enthalpy, and Tsat.

I hope what I've collected here can count toward an "attempt" at a solution. This is not homework. It is a practice problem for the FE exam. This was never covered in my thermo class. I'm sure it is simple, but it is escaping me now. thanks for any help you can provide.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Mar 31, 2012

### HyperSniper

There is a fairly complicated equation on wikipedia for dew point. http://en.wikipedia.org/wiki/Dew_point

If you have all the variables you can just plug and chug. I don't know if that formula is in your FE reference book or not though.