SSC CGL 16 Aug 2015 Shift 1 Paper

There are two specific heats of gases- Specific Heat at Constant Pressure (${\mathit{C}}_{\mathit{p}}$) and Specific Heat at Constant Volume (${\mathit{C}}_{\mathit{v}}$). Heat supplied at constant pressure is used up in two ways: (a) for doing work in expansion and (b) for raising the temperature by 1° C, while at constant volume heat supplied is used only for rise of temperature. Therefore, ${\mathit{C}}_{\mathit{p}}$ is always greater than ${\mathit{C}}_{\mathit{v}}$. They are related as: ${\mathit{C}}_{\mathit{p}}-{\mathit{C}}_{\mathit{v}}$ = R/J. This relation is called Mayer’s Relation