The basic premise of electromagnetic induction is that supposedly when you have a magnetic field moving, it generates an electromotive field perpendicularly, yeah? But if you had a hypothetical space where Newton's first law could be observed perfectly (no external forces at all), and you just had a magnet drifting on for infinity inside a conductive coil, how would that work? There would be no forces acting on the magnet, it would just remain in motion. The electromotive forces would just be coming out of no where then.

  • 1
    $\begingroup$ Have you never done the magnet in a copper pipe experiment? This shows nicely what happens in the situation you describe. $\endgroup$ Apr 15, 2017 at 6:10
  • $\begingroup$ I'm more just wondering in terms of where the energy is coming from and going. I get that the magnet slows its decent, but that should require energy too. Where does that come from, and where does the energy going into the electromotive force come from? $\endgroup$
    – N.D.H.
    Apr 15, 2017 at 6:16
  • $\begingroup$ The magnet induces currents in the pipe and the currents generate a magnetic field that exerts a force on the magnet. $\endgroup$ Apr 15, 2017 at 6:19
  • $\begingroup$ Wow, that's a little bit meta. But again this experiment is not done in a closed system. The force of gravity is where some of this energy is coming from. If I have a magnet that isn't accelerating or decelerating, just floating through space, shouldn't there be no energy to go to the electromotive force? $\endgroup$
    – N.D.H.
    Apr 15, 2017 at 6:22
  • $\begingroup$ If you did the experiment in free fall the magnet would slow asymptotically to a stop. $\endgroup$ Apr 15, 2017 at 6:25

1 Answer 1


When you move a magnet through a coil or even through space , a non conservative electric field is induced in space in a circular form. But, since energy is conserved in any case which can only be possible in this case if the motion of magnet is opposed so that the kinetic energy of moving magnet is converted into electrical energy and if you have a magnet just moving in a straight line with a constant velocity it will ultimately come to a stop, hope that helps, any other question you have regarding this, you can ask me.


Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.