Assetion : Specific heat of a gas at constant pressure is greater than its specific heat at constant volume.
This is because at constant pressure, some heat is spent in expansion of the gas.

Options

A. If both assertion and reason are true and reason is the correct explanation os assertion.
B. If both assertion and reason are true but reason is not be correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

Answer

A

Explanation

In cases of `C_(v),` volume of the gas is kept constant and heat is required only for raising the temperature of one gram mole of the gas through `1^(@)C` or 1 K. No heat, what so ever, is spent in expansion of the gas. In case of `C_(p),` as pressure of the gas is kept constant, the gas would expand on heating. Therefore, some heat is sent in expansion of the gas against external pressure. This in addition to the amount of heat energy required for raising the temperature of one gram mole of the gas through `1^(@)C` or 1 K. Hence specific heat at constant pressure is greater than the specific heat at constant volume.