[Physics] Specific heat capacity for solids of changing temperature

electronicsthermodynamics

I was reading

and I understand that the total energy needed is simply integrating – but how could I calculate the red line in his diagram for a solid? I found the equations for constant volume or pressure but I'm not sure which (if either) would be a good approximation for a solid.

My specific scenario is I would like to calculate the temperature of a wire (let's say copper) as a function of time while a current is passed through it (let's assume this is somehow kept constant, because in actuality the resistance would also be changing as a function of temperature). I know the power dissipated by a wire (or any resistor) is $I^2R$, and I realize using known specific heat capacity of copper at $25{}^{\circ}\mathrm{C}$ would probably give a decent estimate – but if possibly I would like to account for the changing heat capacity.

Best Answer

For a large temperature change, specific heat is a function of temperature. Once that function has been characterized, one can obtain the total heat input as an enthalpy change,$$ \Delta H = \int_{T_1}^{T_2} c\,\mathrm{d}T. $$Note that it is common to curve fit specific heat as a function of temperature, such that specific heat is a polynomial function of temperature (which makes it very easy to integrate).