1. The problem statement, all variables and given/known data its part VI) of a big problem, where: 0.12 moles of argon (40) undergoes the cycle abca described in the graph. Process ab lies on a 540k isotherm. In the previious 5 sub problems, i figured that: Tc=270k Qbc=670J (lost) Qca=400J (added) Wab=370J Wabca=100J The PV diagram has points a,b and c where: a=(1.5X10-3, 3.6X105) b=(3X10-3, 1.8X105) c=(1.5X10-3, 1.8X105) 2. Relevant equations Q=mc[itex]\Delta[/itex]T [itex]\Delta[/itex]U=Q+W [itex]\epsilon[/itex]=1-Qout/Qin=1-Tlow/Thigh 3. The attempt at a solution So it's basically using Qabca to find the efficiecy. The thing is that im not sure what to use for the Qs.