1. The problem statement, all variables and given/known data http://i.imgur.com/jmLqca9.jpg pic of question 2. Relevant equations W = p x dV, Q = dU + W etc 3. The attempt at a solution I know what the different stages are, a-b and c-d are isobaric, d-a and b-c are isochoric and I believe the answer to a, the net work done in one cycle, is zero as dV is zero. but the further questions I'm lost. can anyone help or point me in the right direction?