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What do we mean by minus energy ?

  1. Oct 24, 2009 #1
    what do we mean by"minus" energy ??

    in the classic physics the minus energy express the gain or loss of the particle ..but when we substitute in the quantum theory lows ,the electron has a minus energy ..I think the energy is not like the charge to be minus ..& I can not also imagine any particle even a small one have a minus energy ..!!!!
     
  2. jcsd
  3. Oct 24, 2009 #2
    Re: what do we mean by"minus" energy ??

    Right, all particles in QM have plus energy.
     
  4. Oct 24, 2009 #3
    Re: what do we mean by"minus" energy ??

    It just depends on how you define potential energy...
     
  5. Oct 24, 2009 #4
    Re: what do we mean by"minus" energy ??

    The energy is taken relative to some state (which is defined to have zero energy -- this sometimes happens implicitly). The reason is that in any particular process you only talk about energy differences anyway.

    On top of this: usually the negative energy states refer to bounded states, while positive energy states refer to unbounded states.
     
  6. Oct 24, 2009 #5

    Vanadium 50

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    Re: what do we mean by"minus" energy ??

    Exactly.

    No, xepma has it right.
     
  7. Oct 25, 2009 #6
    Re: what do we mean by"minus" energy ??

    I think this is the logistic reply ..
    I asked a teacher about this ,he told me that if we considered the energy between the electron & the proton equal zero before gravitation ,then the attraction would lead to lose energy & that make the energy of electron always minus (we find that in Bohr's equation)
    but I still don't know what are the results of these sign??
     
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