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A question about electromagnetic induction

  1. Aug 25, 2014 #1
    Hi guys
    I just want to know why changing magnetic flux in a coil induces emf???
    Thanks in advance.
  2. jcsd
  3. Aug 25, 2014 #2
  4. Aug 25, 2014 #3
    Might be a question better posed on the classical physics area of the forum. At any rate, I'm not entirely sure that anyone knows why it happens, just that it does. Through experimentation, and a lot of thinking, we've figured out the equations that seem to predict the behavior; but to know, precisely, why it occurs, so far as I know, eludes us. I suppose one might find some answer looking in QM, but I'm not versed enough in that to tell you yes one way or the other.
    Last edited: Aug 25, 2014
  5. Jun 11, 2015 #4
    Hello people...imagine a magnet placed near a coil of many turns...now instead of moving the coil or magnet...will emf get induced when I force a turbulent Air in the gap between coil and magnet...becaz magnetic flux disturbed by air whose relative permeability changes when it moves turbulently........
  6. Jun 11, 2015 #5


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    I think it will induce an emf. Its magnitude will depend upon the degree of turbulence.
  7. Jun 11, 2015 #6


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    Faraday observed the fact, as stated in Faraday's Law of Electromagnetic Induction. Maxwell later tried to put all the known laws of electricity and magnetism into a few equations, and suggested that a varying magnetic field produces an electric field. The electric field create an EMF between the ends of the conductor.
  8. Jun 11, 2015 #7
    I'm pretty sure the guys over in the quantum physics forum will have an opinion. If you go that route, I might like to see their answer. I doubt I'll understand it, but hope seems a universal constant. :rolleyes:

    I would guess it has something to do with exchanging virtual photons through quantum entanglement.
  9. Jun 11, 2015 #8
    It derives from Lorenz force - a charged particle passing though a magnetic field will have a force applied to it - perpendicular to both the field and the direction of travel, from an EE understanding that should be the deepest it need to be looked at. Beyond that it becomes a discussion for relativity ( Sub atomic charged particles and E-M Fields - however not really entanglement)
  10. Jun 11, 2015 #9

    jim hardy

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    think it's something that was observed and made use of, not something that was figured out a priori from more basic facts.

    F = QV cross B is what pushes the charge Q along the wire,
    just as F= gm1m2/r2 pulls masses toward one another
  11. Apr 22, 2016 #10
    1. change of magnetic feild in space will create change in electric feild despite the presence of conductor or not.-James Cleark Maxwell.

    2. some how placing metal in that space electric feild prefers to flow inside metal rather than vaccum since metal offers less resistance to electric feild flow.

    3. so i think electric feild comes first then the current.

    4. Personally speaking...... Henry Lowrence worked for JP morgan and other capitalists and he Dumbed down Maxwellian and Heavyside equations to never reach overunity.
  12. Apr 22, 2016 #11

    best explanation on magnetism and induction check it bro!!!!!
  13. Apr 22, 2016 #12
    Other answers are good. But for the basic, underlying cause? We don't know.

    The universe acts the way it acts. We observe that action and create models of how it acts based on experimentation. But there's always another "why" somewhere.

    As for why Maxwell's equations work the way they do, it's because the electromagnetic force is a U(1) group. What does this mean? It means Maxwell's equations work the way they do. We know this from observation.

    Science is all about observing and testing those observations. We seek unifying models, but those models are based on observation, not the other way around.

    So there are many answers to your "why" depending on the answer you seek.
  14. Apr 23, 2016 #13
    The fundamental question is Why does an orbiting electron have a magnetic moment. - Or how is the movement of an electron (or charge) create a magnetic field. It is the interplay of these two things that make all of this happen. I had not looked in to this but this seems like a pretty good
    How Special Relativity Makes Magnets Work
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