Physics

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A bar of aluminum (bar A) is in thermal contact with a bar of iron (bar B) of the same length and area. One end of the compound bar is maintained at Th = 75.5°C while the opposite end is at 30.0°C. Find the temperature at the junction when the energy flow reaches a steady state.

  • Physics -

    conductivity iron = FE
    conductivity al = AL

    temp difference over iron = 75.5 - T
    temp difference over Al = T - 30

    (75-T) (FE) proportional to Q
    (T-30) (AL) same proportional to q because areas and lengths the same
    so same Q through each
    (75-T)(FE) = (T-30) (AL)

  • Physics -

    by the way the ratio of AL/FE is about 136/46
    (you don't need units here because all you need is the ratio)

  • Physics -

    Thanks for your help! The only thing is that the AL and FE need to be switched around and then I got the correct answer. There is a picture that I forgot to post that has Aluminum by the 75.5 and 30 next to the Iron. Thanks again!

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