One mole of an ideal diatomic gas undergoes a transition from \(A\) to \(B\) along a path \(AB\) as shown in the figure.
The change in internal energy of the gas during the transition is:
1. | \(20~\text{kJ}\) | 2. | \(-20~\text{kJ}\) |
3. | \(20~\text{J}\) | 4. | \(-12~\text{kJ}\) |