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Homework Help: Estimate its capacitance to earth

  1. Feb 4, 2010 #1
    1. The problem statement, all variables and given/known data

    A telephone wire of diameter 1mm is suspended 10m above the ground. Estimate its capacitance to earth per unit length

    2. Relevant equations



    3. The attempt at a solution
    I've tried to solve the problem by using the formula for a cylindrical capacitor and got the answer but apparently it was wrong. Instead it's supposed to be solved by the mirroing method. So now I'm lost. Help me please :)

    Thx
     
  2. jcsd
  3. Feb 4, 2010 #2
    Re: Capacitance


    Consider two parallel 1mm thick wires a distance 20m apart with opposite charges, same electric field for the above problem. Does that make things easier? I'm not sure.
     
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