Question

Why the specific heat at a constant pressure is more than that at constant volume ?

• A. there is greater intermolecular attraction at constant pressure
• B. at constant pressure molecular oscillation are more violent
• C. external work need to be done for allowing expansion of gas at constant pressure
• D. due to more reasons other than those mentioned in the above

Answer 1

Answer: (C)

external work need to be done for allowing expansion of gas at constant pressure

At constant volume heat supplied is used in increasing the internal energy only, as the work done would be zero.

But in the case of constant pressure, external work need to be done for allowing expansion of gas at constant pressure. Therefore more heat is required in the latter.