1. The problem statement, all variables and given/known data The problem is as following: 2. Relevant equations [itex]\Delta[/itex] E = [itex]\Delta[/itex] Q-[itex]\Delta[/itex] W 3. The attempt at a solution Now I know that if work is done by the system then work sign is negative and that if volume remains unchanged then no work is done. Am I right to say that Internal energy @ C is 50 joules ? How does that answer my question ? I know over all energy is conserved in cycle. Any tips please. Edit i see that the screenshot hasnt loaded i will edir it once i get back home Thanks!