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Homework Help: Calculate the resistance help

  1. Feb 9, 2010 #1
    1. The problem statement, all variables and given/known data
    A number 16 copper wire has a diameter of 1.291mm. Calculate the resistance of a 43m long piece of such wire. Use rho=1.72x10-8 Ohm-m for the resistivity of copper. Use units of "ohm".


    2. Relevant equations
    R=pl/A
    rho is the same thing as the p


    3. The attempt at a solution
    I just dont know the equation for find A. if you can help me with that then this should be simple since both p and l are given as well as d.
     
  2. jcsd
  3. Feb 9, 2010 #2

    tiny-tim

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    Science Advisor
    Homework Helper

    Hi shimizua! :smile:
    The question gives the diameter, so you can assume that the cross-section is circular, and use A = πr2 (= πd2/4). :wink:
     
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