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Homework Help: Resistance of cylinders

  1. May 5, 2014 #1
    1. The problem statement, all variables and given/known data

    can anybody help me with this question? my ans is different from the ans given... i need explaination on this ! here's my attempt by the way.
    r=pl/a . r=resistance , p = resistivity l=length

    r=(1.69e-8)(2pi )(6e-2 +1.5 e-3 )(300) / (pi )(1.5e-3)^2

    what's wrong with my working? p/s e =1 x 10^x

    2. Relevant equations

    3. The attempt at a solution

    Attached Files:

  2. jcsd
  3. May 5, 2014 #2


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    2017 Award

    Staff: Mentor

    You ignored the perfect electrical contact between successive turns. You don't have a single long wire, you have a conducting cylinder.

    Minor detail: this is the outer radius, not the average radius.
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