Jitender Pal
Specific heat at constant pressure signifies that external pressure is kept constant during whole heating process. The heat capacity at constant pressure Cp has more magnitude than that of heat capacity at constant volume. The Cp involves expansion of gas and increment of average temperature of gas. Thus, the supplied heat is diverted to some fraction in expansion work.
However, the heat capacity at constant volume reflects that total supplied heat is actually used in increasing the temperature of gas. Thus, no expansion wok is possible in heating a gas at constant volume. Thus the numerical value of Cp is greater than that of Cv which is shown below.
Cp – Cv = nR
Where n is the number of moles and R is the gas constant.
That is why the specific heat at constant pressure is greater than the specific heat at constant volume.
