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Eddy currents and the motion of the body

  1. Dec 8, 2009 #1
    A solid metallic body moves closer to a magnet. This causes increase in magnetic flux linked with the body. Eddy currents are generated in it.
    Now, the problem is: will the body come back to its original position or will stay there?
    I say that eddy currents will generate heat which will go waste. So, it must stop there/nearby after losing its energy completely.
    But what would happen if energy is not lost as heat, will it come back to its original position so as to oppose the change in flux??So, will it try to make the flux linked with it equal to initial flux?
  2. jcsd
  3. Dec 8, 2009 #2


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    The eddy currents, following Lenz's law, will produce a magnetic force to oppose the motion. If there were 'no' resistance, the currents would be so high that the opposing force would equal the force pushing the object at the magnet. This happens in magnetic 'levitation' when a lead ball is suspended permanently, above a magnet when the temperature is low enough to make the lead a superconductor. You find that it bounces up and down. (There must be a Utube sequence, somewhere)
    As energy is lost, the ball will fall, however; it can't stay where it started.
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