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Field inside conductor-is it zero every where?

  1. Feb 27, 2012 #1
    field inside conductor-is it zero every where??

    consider a perfectly spherical neutral conductor.suppose a few electrons with net charge q is deposited on it.the electrons will spread out[due to mutual repulsion] and distribute themselves in such a way that the net field inside the sphere is zero.i can understand that at the exact centre of the sphere the fields of individual electrons will cancel each other out.but as one moves away from the centre and towards the centre,the net field by electrons on the side of the surface TOWARDS WHICH we are moving will exert a stronger field than the side FROM WHICH we are moving away.in effect, the field[negative] will grow stronger and stronger as we move towards the surface.
    doesn't this mean that field is not zero anywhere in the sphere except the exact centre??
    and what about surfaces that are not spherical.for eg,if i am sitting inside the frame of a car[with all non-conducting parts removed] and the car is struck by lightning,will i be feeling zero electrical field at every point on my body??
  2. jcsd
  3. Feb 27, 2012 #2
    Re: field inside conductor-is it zero every where??

    There is a gigantic number of electrons in the sphere. Not just the few you added. And with such a huge number of electrons it's possible for them to arrange in such a way that there is no field inside the conductor. If there was any field inside, it would cause electrons to move until the field is cancelled out. And it doesn't matter what shape the conductor has. The field is always zero as long as there is only static charge.
    If there is a current flowing e.g. a lightning strike, then there can be fields inside the conductor but only as long as the current is flowing.
  4. Feb 27, 2012 #3
    Re: field inside conductor-is it zero every where??

    that's the key....you assume a static field configuration,equilibium conditions, any charges moves to neutralize and reach a static configuration ....'conductor' means charges move around really easily, so they easily arrange themselves to produce a virtually zero net field everywhere.

    If you want more, search these forums for "charge on a conductor' or similar and yopu'll find the same descriptions apply even when many electrons are supplied to a current carrying conductors.
  5. Mar 13, 2012 #4
    Re: field inside conductor-is it zero every where??

    an electric field due to one particle exists even if there is no other particle to interact with,right? at the exact centre of the sphere,the fields coming from all directions will cancel out completely.move even a little away from the centre,the field would not be an exact zero[there are no particles,charged or uncharged, inside the sphere],correct?

    to round it up,am i right in saying that the field,when no other particles inside the sphere is exactly zero only at the exact centre;but when an object is kept anywhere inside a sphere,the electrons on the sphere would re-arrange themselves,so that the field on the object is zero?
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