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Math Help - I am not sure i solved right I got 400

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    I am not sure i solved right I got 400

    The exhaust temperature of a Carnot heat engine is 350oC. What is the intake temperature if the efficiency is 25.0%?


    400oC

    543oC.

    558oC

    830oC
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  2. #2
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    Quote Originally Posted by jaycas21 View Post
    The exhaust temperature of a Carnot heat engine is 350oC. What is the intake temperature if the efficiency is 25.0%?


    400oC

    543oC.

    558oC

    830oC
    I presume you are talking about an exhaust temperature of 350 degrees C and not 3500 degrees C? For a Carnot engine:
    \epsilon = 1 - \frac{T_o}{T_i}
    where \epsilon is the efficiency, T_i is the intake temperature, and T_o is the output (exhaust) temperature.

    So
    \frac{T_o}{T_i} = 1 - \epsilon

    T_o = T_i(1 - \epsilon)

    T_i = \frac{T_o}{1 - \epsilon}

    So in your problem:
    T_i = \frac{350 \, ^oC}{1 - 0.25} = 466.667 \, ^oC

    -Dan
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