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Kirchhoff's First Rule - Electrical Charge / Energy Conservation

  1. May 5, 2009 #1

    I've read that Kirchhoff's first rule is a statement of electrical charge conservation. However, currents are electrical charge in movement, so isn't it possible to say that it also follows the law of conservation of energy?

  2. jcsd
  3. May 5, 2009 #2
    Hi there,

    In this sense, not really. Kirchoff's first rule says that current entering a knot must exit. It has nothing to do with the speed of the charges, which can be slowed down in the process. It can even be that electrons are "swpped" in the conduction process, with electrons from other atoms.

    You should not forget that the current is a convention wich describes the motion of the positive charges in a conductor. Since we now know that it is the negative charges that are mobile in a conductor, on has little relation with the kinetic energy of them.
  4. May 5, 2009 #3
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