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Homework Help: Reversible heat engines

  1. Oct 22, 2007 #1
    [/B]1. The problem statement, all variables and given/known data

    What is the maximum amount of mechanical work that can be got by a reversible engine working from a finite heat source of thermal capacity, C=1000J/K, if it is initially at 373K and the engine discharges to a bath of virtually infinite heat capacity at 273K?
    [You may take C as a constant over the temperature range, 273K - 373K]

    2. Relevant equations

    Good question...!

    3. The attempt at a solution

    Well, I know that W=Q1-Q2, which is also =Q(T1-T2)/T1. I also know that W=(integral of)Pdv, and that Q=mc(deltaT). However, I can't see how to get the values for P or Q. To begin with, I'm not sure whether I should treat it as a Carnot engine, since most reversible ones are, but not all of them. And if so, should I treat the entropy (S) as 0, which might help? I worked out deltaS = Cln(T2/T1) = -312.1066, which I don't know if it is right and if it will help anyway!
    Any help at all will be appreciated!
  2. jcsd
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