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Wikipedia electric charge page confusion

  1. Sep 1, 2015 #1
    Why does Wikipedia's page on electrical charge have a picture of a positivity charged object with arrows going to a negatively charged object? Doesn’t electrons flow from a negatively charged object to a positively charged object? Or is the picture just showing conventional current?


  2. jcsd
  3. Sep 1, 2015 #2


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    Those lines are just the electric field lines, it has nothing to do with electron current. The significance of drawing electric field lines comes out, for example if one wants to draw equipotential surfaces, which is a surface on which every electric field line must pierce through perpendicularly.
  4. Sep 1, 2015 #3
    So an electric field goes from positive to negative?
  5. Sep 1, 2015 #4


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    Giving an arrow to the electric field lines is just a convention, it's not like the positive charge acts as an electric field emitter and the negative charge as the receiver. Electric field lines can also indicate the electric field strength dependence on position, the denser the lines the stronger the field there. In your picture, we can infer that the electric field strength is stronger around either charges and gets weaker as one goes farther from both of them.
  6. Sep 1, 2015 #5
    Ah, so you could say that it would be a better representation to put arrows going in both directions on those lines.
  7. Sep 1, 2015 #6


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    No matter how you look at it, assigning one arrow (either direction) to each line is better than two arrows of opposite directions because this way you don't always need to draw the charge type on all existing charges in the system.
  8. Sep 1, 2015 #7
    Appreciate you helping dude.
  9. Sep 1, 2015 #8


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    No. Positive and negative charges will experience opposite forces from any given electric field. The arrows give us a way of visualizing this. A positive charge will feel a force in the direction of the arrows while a negative charge will feel a force in the direction opposite that of the arrows. So in your picture the positive charge is pulled towards the negative charge, which is with the arrows, while the negative charge is pulled towards the positive charge, or against the arrows. Both end up meeting in the middle, assuming they were free to move.
  10. Sep 2, 2015 #9


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  11. Sep 2, 2015 #10
    The direction of the electric field at any point is (by definition) the direction of the force experienced by a small, positive probe charge placed in the field at the given point.
    It could have been defined based on a negative probe but it just wasn't.
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