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Can somebody explain this?

  1. Sep 6, 2007 #1
    http://hyperphysics.phy-astr.gsu.edu/hbase/electric/farlaw.html#c2
    Why, first, when the magnetic field is approaching with the N pole, the electrons are opposing on the increase of the field? Why when N is receding, the electrons are going into direction of the move of the magnet?
     
  2. jcsd
  3. Sep 6, 2007 #2
    It's experimentally seen -- Lenz's law.
     
  4. Sep 6, 2007 #3
    you can have a feel if u draw lines.When n pole is approaching the electrons will face a force that will take them away from it and vice versa.
    Hope it helps!!
     
  5. Sep 6, 2007 #4
    what force? attractive or repulsive?
     
  6. Sep 6, 2007 #5
    I won;t tell u to mug it up.Just calculate from the frmula q(v*B)
     
  7. Sep 6, 2007 #6

    Doc Al

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    Staff: Mentor

    What do you mean by "the electrons are going into direction of the move of the magnet"? Do you mean that the electrons are going from left to right, the same direction that the magnet is moving? If so, realize that the arrow refers to conventional current, not electron flow (electrons move in the opposite direction). Also realize that the sideways movement of the current depends on how the coil is wound.

    You've asked similar questions many times, so I don't know what kind of answer you are looking for when you ask "why" this happens. Is there something special about when the N pole is receding that puzzles you? Or do you have the same question about all four examples on that page?

    Note that in all cases the induced magnetic field acts so as to resist any change in the magnetic field within the coil. (This is Lenz's law.) When the N pole is pulled away from the coil that implies a decreasing field towards the coil--thus the induced magnetic field must act to increase the field in the coil. To create such a field, the induced current must travel as indicated in the coil.
     
  8. Sep 6, 2007 #7
    But if on the first example, it opposes the increasing of the field, how then when the magnet is going back the field is decreased?
     
  9. Sep 6, 2007 #8
    the current opposes the change in field. so if the field is high and it decreases then current opposes this change by creating more field and vice versa.
     
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