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I am new here, this is more of a conceptual confirmation than mathemab

  1. Apr 30, 2014 #1
    When a wire resists an electrical current it produces heat energy. But how efficient is this transfer? If the electrical Power is 20watts is the heating power 20watts? (ignoring all other inefficiencies, just the conversion from Electrical to Heat)

    I'm thinking since a circuit requires electrons to complete the circuit in order to have a current, the Powers won't be equal because some energy will remain within the electrons to keep them in movement.

    However I am not certain of this and growing less and less confident of this idea. Could someone explain this in a way I can understand?
  2. jcsd
  3. Apr 30, 2014 #2


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    Staff: Mentor

    The heat comes from the electrons losing potential energy, not kinetic energy. The electrons move at the same (very slow) speed before and afterwards, if the wire maintains the same diameter and resistivity.
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