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A question about refrigerators and energy

  1. Feb 28, 2009 #1
    1. The problem statement, all variables and given/known data

    The coefficient of performance of a refrigerator is 5.40. The compressor uses 30.0 J of energy per cycle.

    a) How much heat energy is exhausted per cycle?
    b) If the hot-reservoir temperature is 27.0C, what is the lowest possible temperature in C of the cold reservoir?

    2. Relevant equations


    QH = QC + Win

    3. The attempt at a solution

    solved part a) and found the energy to be 192 J

    i keep on getting part b) wrong though and I ran out of chances to try.

    please help!
  2. jcsd
  3. Feb 28, 2009 #2


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    What is the COP (coefficient of performance) in terms of Qh, Qc, and/or W?
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