Question

In a given process on an ideal gas dw = 0 and dQ < 0. Then for the gas 

(A) the volume will increase 

(B) the pressure will remain constant 

(C) the temperature will decrease 

(D) the temperature will increase

Answer 1

Correct option: (C) the temperature will decrease

Explanation:

dQ = du + dw

As dw = 0, dQ = dU

As dQ < 0 means dU < 0

As dU = [(nfR dT) / 2] means dT < 0 i.e. temperature will decreases also for ideal gas, internal energy can decrease only by temperature decrement.