A Carnot refrigerator is operated between two heat reservoirs at temperatures of 320 K and 270 K. (a) If in each cycle the refrigerator receives 415 J of heat energy from the reservoir at 270 K, how many joules of heat energy does it deliver to the reservoir at 320 K


  1. Answer:

    Qh = -491.85J

    (It is negative due to rejected heat)


    In the question, the heat received by the refrigerator is at the cold reservoir where Qc= 415J

    Now, we are looking for Qh.

    Thus, using thermodynamics equation, we have;

    Qc/Qh = — Tc/Th

    Making Qh the subject, we obtain ;

    -(QcTh)/Tc = Qh

    Plugging in the relevant values, we obtain ;

    -(415×320)/270 = – 132800/270 =

    – 491.85J

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