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Homework Help: Electric field magnitude at large distances

  1. Oct 13, 2006 #1


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    I have a question which basically asks me to show and explain why electric field magnitude a very large distance r from an electric dipole falls away as approximately 1/r^3.

    Can anyone point me in the right direction of thinking?

    Could it be because the electric field lines are spread out more rapidly over a larger area of space?

  2. jcsd
  3. Oct 13, 2006 #2
    You could start off by doing mathematically, setting up a dipole configuration and taking the electric field at a point r not so far away.

    Then take it to be VERY far away...and you should be able to see how it boils down to 1/r^3.

    Now as to an actual explanation as to why this happens...try to dig in and understand how the mathematics explain what is going on.
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