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Homework Help: Find the Potential as a function of position

  1. Jan 31, 2007 #1
    1. The problem statement, all variables and given/known data
    A rod of length L carries a charge Q uniformly distributed along its length. The rod lies along the y-axis with one end at the origin. Find the potential as a function of position along the x-axis


    2. Relevant equations
    [tex]dV=\vec{E}\cdotp d\vec{l}[/tex]

    [tex]V=\frac{kq}{r}[/tex]


    3. The attempt at a solution

    I think I am to use the first equation posted, but I am not sure how to relate it to the x-axis, if the rod lies along the y-axis. Also, what is the displacement here? I am assuming it is just dy?
     
  2. jcsd
  3. Jan 31, 2007 #2

    Andrew Mason

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    Homework Helper

    You have to integrate along the rod from y = 0 to +L.

    [tex]V(x) = \int_{0}^{L} \frac{k}{r}dq[/tex]

    Work out the expression for dq in terms of dy. Work out the expression for r in terms of x and y (think: Pythagoras).

    AM
     
    Last edited: Jan 31, 2007
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