 The latter is formula_60, where formula_61 is the change in the sample's volume in that infinitesimal step.Therefore
hence
If the volume of the sample (hence the specific volume of the material) is kept constant during the injection of the heat amount formula_59, then the term formula_65 is zero (no mechanical work is done).Then, dividing by formula_9,
where formula_68 is the change in temperature that resulted from the heat input.