Question

Which of the following is correct for a free expansion process?

• A. $dU=0$
• B. $dQ=0$
• C. $dW=0$
• D. All of these

Answer 1

The correct option is D All of these

Since free expansion is expansion against vaccum, there's no work done. Also, the container is insulated, so heat transfer is zero.

Using the first law of thermodynamics.

$dQ=dU+dW$

$\therefore dQ=dW=0$

$\therefore dU=0$