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A Charged metal Sphere [does charge move around]

  1. Aug 11, 2012 #1
    For a charged metal sphere of charge "+q" is the following statement true ?

    all the excess charge is in static equilibrium

    The statement basically implies that the excess charge on the surface can't (and does not) move, hence supporting the theory that the Electric Field lines emerging from the metal sphere are always perpendicular to the surface .

    Otherwise there would be a component of Electric field parallel to the charged surface thus would move the charge inside the metal sphere.

    If it is, how does one come about this statement, and what is the reason for assuming it .
  2. jcsd
  3. Aug 12, 2012 #2


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    for a conductor in equilibrium, all the excess charge is in static equilibrium

    (if the conductor isn't in equilibrium, then all bets are off :wink:)
  4. Aug 12, 2012 #3
    I dont quite get your point.

    Firstly, a metal is a conductor (all metals are)

    secondly, what exactly do u mean by A Conductor/metal in equilibrium ?

    Remember that i am asking about a positively charged metal sphere.

    By the link you provided, it says :

    In equilibrium, the charge inside a conductor is zero, and the density of charge at the surface is greater...

    the statement basically states that for a metal sphere, the excess charge is distributed evenly at the surface hence no excess charge exists INSIDE of the sphere.

    That is what i understand from the link you provided ^^ ... am i right in thinking that way ?

    If i am right, then moving on to the bedrock of this discussion , is the excess charge (which only lies on the surface of a metal sphere) in static equilibrium ?
  5. Aug 12, 2012 #4


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    yes :smile:

    in equilibrium, the charge stays on the surface of any conductor

    (and if the conductor is a sphere, and if there is no external field, then by symmetry the charge will be distributed evenly)
    if the charge is in equilibrium, then the charge is in equilibrium

    if it isn't, then it isn't

    for example, if a charged sphere is brought near another charged object, the charge will rearrange itself … while it's rearranging, it's not in equilibrium
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