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Magnetism to electrism

  1. Dec 10, 2014 #1
    hello!

    If I rotate a metallic cylinder that is a permanent magnet, it will generate electricity in a wire next to it?

    for how long it will generate electricity? forever? or it phases out as the magnetic energy transforms to electricity? how long it will last approximately?

    thanks
     
  2. jcsd
  3. Dec 10, 2014 #2

    russ_watters

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    Staff: Mentor

    The magnet can't just be a cylinder, it needs to be polarized. Individual magnets arranged in a circle would do it. You are roughly trying to describe a generator.

    And it will continue to generate electricity until you stop rotating it or its parts wear out. In the real world, that takes several decades.
     
  4. Dec 10, 2014 #3
    thanks
    why it can't be a cylinder?
    I can only use a cylinder or a tube! isn't there a way to be it magnetic?
    also, can I make it magnetic? will it still take decades to phase out? it will give electricity for decades? what amount of electricity?
     
  5. Dec 10, 2014 #4

    CWatters

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    Science Advisor
    Homework Helper

    A magnet is not a source or store of energy.

    Ultimately the energy produced comes from whatever is spinning the magnet. The energy does not come from the magnet so it doesn't "wear out" the magnet.
     
  6. Dec 10, 2014 #5
    how is not magnet a store of energy? it has the potential to produce work by moving a magnetic item!
     
  7. Dec 10, 2014 #6

    russ_watters

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    So this is for an assignment? Without knowing the details of the assignment, I'd just be guessing about what you should do.
     
  8. Dec 10, 2014 #7

    russ_watters

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    That work is symmetrical/conserved. And more to the point, the magnetic field isn't consumed when doing the work. Picture it like a mass bouncing on a spring.
     
  9. Dec 10, 2014 #8

    berkeman

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    Staff: Mentor

    Here is some introductory reading that should help you understand how magnet-based generators work:

    http://en.wikipedia.org/wiki/Electric_generator

    :-)
     
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