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What charges a proton?

  1. Jun 3, 2007 #1
    What makes and gives a proton a postive charge and an electron a negative charge?
  2. jcsd
  3. Jun 3, 2007 #2


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    I'm not sure of your question....... If your asking why is a proton "positive" and an electron "negative", it is because we named them that because of the way the two types of charges seem to cancel each other out. We could have just as easily called a proton negative and an electron positive and we would get the same results.

    If you are asking why do protons and electrons have charge in the first place, I don't think anyone has an answer to this question. As far as we know, it is just the way nature happens to be.
  4. Jun 3, 2007 #3


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    their instrinct properties I guess, well the proton is considered to be build of quarks which carries charges in fracions of 3. But as GO1 wrote, it is just they way nature is.
  5. Jun 3, 2007 #4
    thanks for the help! :)
  6. Jun 3, 2007 #5


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    It's still not clear whether you were asking about the origin of charge itself,
    or just why proton is +1 and electron is -1. I'll assume the former, since that
    question is more interesting... :wink:

    All intrinsic properties of elementary particles have their origin in how
    they transform under certain symmetry groups. In the case of electromagnetism,
    the group is U(1), i.e: multiplication by a phase factor exp(i theta). For this
    group, there are 2 inequivalent representations: you can multiply by
    exp(i theta), or by its complex conjugate exp(-i theta). Elementary particles
    can be classified by how they transform under such symmetry groups, i.e:
    the Poincare group of special relativity, and certain internal symmetry
    groups - of which electromagnetic U(1) is just one. The number of different
    inequivalent representations of these groups determines how many different
    charges there are. In the case of U(1), there are two inequivalent
    representations as I mentioned above, and this manifests in nature as
    two different electric charges.

    The question of whether all this is genuinely "explanatory" or merely
    "descriptive" is debatable - but I still think it's interesting, and the whole
    group theoretic approach to elementary particles has been stunningly
    successful over the past 50-60 years.
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