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How to find the temperature of the cold reservoir?

  1. Feb 18, 2016 #1
    1. The problem statement, all variables and given/known data

    Carnot engine A has an efficiency of 0.60, and Carnot engine B has an efficiency of 0.80. Both engines utilize the same hot reservoir, which has a temperature of 650 K and delivers 1200 J of heat to each
    engine. Find the magnitude of the work produced by each engine and the temperatures of the cold reservoirs that they use.


    2. Relevant equations
    The equation I used: e(carnot)=1-Tc/Th

    3. The attempt at a solution
    Tc=1-e(carnot)*Th
    Tc= 1-0,60*650
    Tc= -389 K
     
  2. jcsd
  3. Feb 18, 2016 #2

    DrClaude

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    Staff: Mentor

    You didn't isolate Tc correctly.
     
  4. Feb 18, 2016 #3
    What's the right way to do it?
     
  5. Feb 18, 2016 #4

    DrClaude

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    Staff: Mentor

    The equation
    $$
    e = 1 - \frac{T_c}{T_h}
    $$
    is correct, but that doesn't mean that
    $$
    T_c = 1 - e T_h
    $$
    Start by moving the 1 to the same side as ##e##.
     
  6. Feb 18, 2016 #5
    Okey, tnx
     
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