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Homework Help: Looking a electrical potential far away

  1. Jun 8, 2010 #1
    1. The problem statement, all variables and given/known data


    V=(KQ/L)((-ln(d))+(ln(L+d)))

    is this correct? if not could some one tell me where i went wrong.
    thanks in advance.

    there is a part 2 to it as follows:

    Imagine that distance d is much greater than the length of the rod. Intuitively, the potential should be approximately the same as the potential at a distance d from which of the following charge distributions?

    a) an infinitely long wire with total charge Q
    b) an infinitely long wire with total charge Qd/L
    c) a point charge of magnitude Q
    d) an electric dipole with moment QL

    V=(KQ/L)((-ln(d))+(ln(L+d)))

    not sure what the question trying to interpret, if i am correct as d>>L the charge becomes like a point charge

    2. Relevant equations

    V=(KQ/L)((-ln(d))+(ln(L+d)))

    3. The attempt at a solution

    so my claim is that as we go far we see it as a point charge. but i am not sure about this could someone explain this?
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Jun 8, 2010 #2

    kuruman

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