Define two principle specific heats of a gas. Which is greater and why ?

At constant pressure : the quantity of heat necessary to increase the temperature of unit mass of a gas through one degree is called specific heat of the gas at constant pressure.
${\mathrm{C}}_{\mathrm{p}}=\frac{\mathrm{\Delta Q}}{\mathrm{m\Delta t}}$
SI unit : $\mathrm{J}{\mathrm{Kg}}^{-1}{\mathrm{K}}^{-1}$
At constant volume : the quantity of heat necessary to increase the temperature of unit mass of a gas through one degree is called the specific heat of the gas at constant volume. It is denoted by c_v.
$\therefore {\mathrm{c}}_{\mathrm{V}}=\frac{\mathrm{\Delta Q}}{\mathrm{m\Delta t}}$
SI units: $\mathrm{J}{\mathrm{Kg}}^{-1}{\mathrm{K}}^{-1}$
The amount of heat ‘Cv’ used to increase internal energy only. But the amount of heat ‘Cp’ used to increase internal energy and to do external workdone.
Hence Cp>Cv