The problem asks: A heat engine takes in 1000J of energy at 1000K and exhausts 600J at 500K. What are the actual and maximum theoretical efffiencies of this heat engine? I know the MTE is 1-Tc/Th = 1-500/1000 = .50 = 50% I'm not sure if I calculate the actual the same way with the Joules, or if I use n=W/Q? If so, that would be 600J/1000K = 60% which would be higher than the MTE. Doesn't seem right... Would the correct equation for the actual work be 1-600J/1000J = 1-.6 = .4 = 40% ?