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Homework Help: Carnot engine efficiency and exhaust problem

  1. Nov 15, 2008 #1


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    1. The problem statement, all variables and given/known data
    The exhaust temperature of a Carnot heat engine is 121◦C. What is the intake temperature if the efficiency of the engine is 13.4 %? Answer in units of ◦C.

    2. Relevant equations

    3. The attempt at a solution
    This seems like just a plug and chug problem:
    Th=139.723 ◦C
    However, this answer is wrong-according to my Quest web homework. Am I missing something here? Thanks
  2. jcsd
  3. Nov 15, 2008 #2


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    Homework Helper

    Hi lzh,

    The Celsius scale is not a thermodynamic temperature scale. You need to use a temperature scale such as Kelvin here.
  4. Nov 15, 2008 #3


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    Oh! I see! Thanks! I got it now!
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