Question

A closed tank containing air is stirred by a paddle wheel. The work input to the wheel is $40\text{J}$ and the heat transformed to the surrounding from the tank is $10\text{J}$. The external workdone by the system is

• A. $10\text{J}$
• B. $40\text{J}$
• C. $30\text{J}$
• D. Zero

Answer 1

The correct option is D Zero

This is the case of constant volume process or an isochoric process. By performing work on the system temperature can be raised.


But, in an irreversible isochoric process, system doesn't perform work on the surrounding at expense of its internal energy.