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Why negative sighn in faraday law of electromagnetic induction?

  1. Nov 14, 2009 #1
    plzzzzzzz any one can clear me on this point:
    why -ve sighn comes in faraday law of electro magnetic induction?what is it sighnificance?if in answer value of induce EMF become -ve than waht will be its direction.
     
  2. jcsd
  3. Nov 14, 2009 #2
    The minus sign expresses Lenz's law which in turn expresses the conservation of energy.........."the induced emf is in a direction such that it opposes the change producing it".As an example if you push a magnet towards a coil on closed circuit the induced current will cause the coil to become magnetised in a direction such that it repels the magnet.The work done in overcoming this repulsion is converted to electrical energy.
     
  4. Nov 14, 2009 #3
    if the -ve sighn is removed then what will be done with this law?
     
  5. Nov 14, 2009 #4

    Doc Al

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    Last edited by a moderator: Apr 24, 2017
  6. Nov 17, 2009 #5
    i mean that if we assume that lenz's law is wrong then what will happen?
     
  7. Nov 17, 2009 #6

    Doc Al

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    For one thing, energy will not be conserved--you'll have a source of "free" energy.
     
  8. Nov 17, 2009 #7

    Redbelly98

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    Then we get a contradiction between what the law says and what is actually observed.
     
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