3. For a system consisting of two phases in equilibrium P is a function of T only, so that
$$ \left( \frac{\partial p}{\partial T} \right)_v = \left( \frac{\partial p}{\partial T} \right)_s = \frac{dp}{dT} $$, show that ratio of sp. heat at const vol and adiabatic compressibility could be given as
$$ \frac{C_v}{\kappa_s} = TV \left( \frac{dp}{dT} \right)^2 $$ for such a system regardless of the nature of transition between the phases.
