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B Magnetic field strength over distance

  1. Sep 24, 2016 #1
    I want to know how does distance affect the magnetic field of a permanent magnet. I have read about the inverse square law and how it could apply to magnetic fields over growing distances, but doing so, I read about monopoles, which is a new concept to me. So, for the time being, I would like a link that explains monopoles and an equation that fulfills my needs for my project.

    Thank you.
  2. jcsd
  3. Sep 24, 2016 #2


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    Magnetic monopoles: https://en.wikipedia.org/wiki/Magnetic_monopole

    Magnetic monopoles are essentially the magnetic version of an electric charge. I can charge an object to negative or positive and the field emanating from that object obeys the inverse square law in regards to field strength. Magnetic monopoles would behave similarly, except with a magnetic field instead of an electric field.

    However, magnetic monopoles do not exist. You cannot break a magnet into single poles, as the wiki article explains.

    In a magnetic dipole, which is what most permanent magnets are, the strength of the magnetic field falls off with the cube of the distance. So they obey an inverse-cube law (1/r3).
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