1. The problem statement, all variables and given/known data The question is: An ideal heat engine takes in heat Q(in) at a temp T(h). It exhausts heat Q(out). So: (a) how much work is done by engine (b) what is efficiency of engine (c) what is exhaust temp of engine and (d) calculate the answers to above for heat input of 460J at a temp of 600K and heat output of 285J. 2. Relevant equations 3. The attempt at a solution So I have done so far: (a) W = Qin - Qout (b) E = W/Qin but (c) is the bit that confuses me! so far I have got: deltaS = deltaQ / T = (Qin - Qout) / T(h) now after getting the above answer for deltaS, do I now rearrange it to get T = deltaS x deltaQ and plug that answer into this equation to get the final temp? So to use the figures supplied would look like this: deltaS = deltaQ / T = (460 - 285)J / 600K = 0.29 JK (not sure what the unit is here?) now plug into: T = deltaS x deltaQ = 0.29 x 175J = 51.04 (again not sure what unit?) I'm a bit lost here - am I on the right track or waaaaaay off??? Thanks heaps.