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Electric fields

  1. Mar 8, 2006 #1
    Why do like electrical charges repel and opposite charges attract? Is it to do with obtaining lower energy levels through movement?
  2. jcsd
  3. Mar 8, 2006 #2


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    The real question would be, why do charges exist, and why only positive and negative? Why don't we have charge A, charge B, and charge C? This is something rather hard to answer and can be questioned indefinitely. You'll probably need to ask a string theorist :P

    I believe we came to the discovery that if we take "charged" objects and put them close together they would repel. Sometimes they would attract. Then at one point, a stroke of genius hit man, and voila we have the positive and negative charge that repel like charges and attract opposites. It has nothing to do with lowering of energy. It's just a fundamental concept of our universe. Another question to you: why do masses attract each other? Why do masses exert gravity?
  4. Mar 8, 2006 #3


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    In Zee, (QFT in a nutshell), there's a (slightly handwaving, but interesting) argument that explains that the deep origin of this effect is due to the electromagnetic interaction being described by vectors. This gives rise to like charges repelling (and hence opposite charges attracting). A 2-tensor field, such as gravity in GR, according to the same argument, turns out to be attractive for like "charges".
  5. Mar 8, 2006 #4

    Claude Bile

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    Charge is one of those fundamental concepts you can't really explain on a more fundamental level, it is simply a property that we observe some objects to possess. While charged particles will act to minimise their energy, this fact does not explain why a particular action ought to minimise its energy (I hope that makes sense :rolleyes:).

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