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Electrostatic induction

  1. Apr 28, 2013 #1
    1. The problem statement, all variables and given/known data
    If there is a positively charged rod,which is placed near an aluminium foil,free electrons in the foil are pulled towards the rod.This makes the top end of the foil negative and leaves the bottom end short of electrons to become positive.

    I wonder if the rod has a very large positive charge(e.g.10+),will it be strong enough to pull the electrons in the aluminium away from the foil?

    So the "remaining part" of the foil(which is positively charged ion) will either decompose due to its
    enormous internal repulsive forces between ions(as there are no electrons) or attract electrons from the surroundings(e.g.air) so as to become electrically neutral?

    Is it possible for a substance to have a high positive charge in solid state?

    I hope someone will understand what I am saying :(,it seems to be nonsense.

    Thx.



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Apr 29, 2013 #2
    "Is it possible for a substance to have a high positive charge in solid state?"

    Yes. The electrons that leave the foil are those which are easily "torn" from the atoms. Understand that you can't simply remove all of the electrons from the object. The other electrons are very tightly bounded to the nucleus and can't really be separated from the atom. But once you've removed the loosely bounded electrons, you now how a positively charged object. Objects can only become positively charged by losing electrons, not gaining protons.


    "So the "remaining part" of the foil(which is positively charged ion) will either decompose due to its
    enormous internal repulsive forces between ions(as there are no electrons) or attract electrons from the surroundings(e.g.air) so as to become electrically neutral?"

    It would take an extremely massive loss of electrons for the foil to decompose in the way you're describing. I don't think that a rod with a massive amount of charge has enough strength to pull all of the electrons away from the foil.

    If this foil was out in the air, then it would pull negatively charged particles from the air to it until it becomes neutral. This is why a balloon with a electric charge will lose its charge after a couple hours.


    In general, I don't believe a solid object can have an extremely large positive charge like you're describing. Objects are bound together by the sharing of electrons. Once they're gone, the atoms have no reason to stick together and will repel and separate.

    Does this answer your question?
     
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