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Homework Help: Introducing Local Charge to Conductors?

  1. Jun 19, 2016 #1
    1. The problem statement, all variables and given/known data
    Is it possible to introduce local charge on a conductor?
    2. Relevant equations
    3. The attempt at a solution
    I know that electrons can move freely from atom to atom in the conductor, so if you introduce excess electrons to the conductor, they'll spread out and there won't be a local charge. But, in this situation, would there be a local charge that only lasts for a moment, before all the electrons are able to spread out across the conductor, moving from atom to atom?

    Also, if you transferred some electrons from the conductor to another object, would it have a locally positive charge in the area where electrons were lost or would those protons spread out as well, moving from atom to atom? I think this would happen because I think only electrons can move freely in conductors, not protons, but I'm not sure.

    Also, could the protons and electrons in a conductor repel each other so that they separate and one side of the conductor would be positive while the other side would be negative?
  2. jcsd
  3. Jun 19, 2016 #2
    There is a definite speed with which the electrons can move ,even on a conductor. So yes, there would be a momentary 'local charge' before the electrons distribute over the conductor.

    If some electrons are lost from the conductor, the 'positive charge' thus created will spread over the conductor. A positive charge is viewed as a deficiency of electrons. When a deficiency is created over a particular area, electrons from rest of the conductor flow towards the area to relieve the deficiency. This causes the deficiency to spread over the whole of the conductor in a symmetrical fashion. Also, you are right in saying that protons don't move in a conductor.

    You can use the analogy of a sea or an ocean. Think that you added some water(electrons) to the ocean(electrons in the conductor). The added water would naturally spread all over the ocean so that the water level is equal at all places. Now think that you removed some water from the sea (that would be similar to creating a positive charge on our conductor).water from neighboring areas would gush in to fill the void created by us; this would proceed till the water level is same all over.
  4. Jun 20, 2016 #3
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