# Prove n =1 for pv^n=C, when temperature is constant

1. Jan 19, 2013

### nu_hash

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

Show that an isothermal process can be regarded as a special case of a polytropic process and deduce what value of n applies in this case.

2. Relevant equations

$P_{1}V_{1}^n = const$

3. The attempt at a solution
$P_{1}V_{1}^n = mRT_{1}$
$P_{2}V_{2}^n = mRT_{1}$

(since temperature is constant $T_{2} = T_{1}$)

therefore:
$P_{1}V_{1}^n = P_{2}V_{2}^n$

but i dont think this proves that n=1 for a isothermal process

2. Jan 19, 2013

### dikmikkel

Edit: What I wrote was nonsense sorry.