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Homework Help: Total resistance!

  1. Sep 8, 2009 #1
    1. The problem statement, all variables and given/known data

    Two 1275m long wires are connected in parallel. One conductor is copper at 1.11mm in diameter and the other is aluminum at 2.23 mm in diameter. Find the total resistance of wires at 25 C, at 105 C, and minus 40 C.

    2. Relevant equations


    3. The attempt at a solution

    I thought I would just look up the resistivity and plug into the equation above.....but then how do I incorporate temperature?
  2. jcsd
  3. Sep 8, 2009 #2


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    Staff: Mentor

    The resistivity listed will be at some temperature, typically 25C (room temp.). There will also be a coefficient of temperature, where the resistivity increases with temperature. You will need to find that for each material, and incorporate it into your calculations.
  4. Sep 8, 2009 #3
    O ok thank you. That was not in my notes!
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