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Homework Help: Divergence Meaning

  1. Feb 19, 2009 #1
    1. I was just trying to understand what divergence means so I hope someone can help me out.

    Well from what I have read if I take a vector field and use an infinitesimal region, if the vector going in is smaller than the vector going out there is positive divergence.

    Does this mean if i make a circle with UNIT VECTORS there is ZERO divergence. Because `what is going in`, is the same as going out,

    [URL][PLAIN]http://img11.imageshack.us/img11/9028/31455816et8.jpg [Broken]

    If they were NOT unit vectors or vector of the same magnitude then there Would be divergence? is that the correct concept?

    2. Relevant equations

    3. The attempt at a solution
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Feb 19, 2009 #2


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    Hi salman213! :smile:

    If you mean unit vectors all going out from a particular point, and a small circle round that point, then there is divergence, because all the vectors are going out of the circle.

    Zero divergence means conservation of whatever-it-is …

    often you have zero divergence everywhere except at "sources" and "sinks" …

    eg an electric field with zero divergence except at the "singularities" where point charges are.
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