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Electricity and magnetism

  1. Jul 13, 2012 #1
    hi , i wanted to ask why does current in a wire produces a magnetic field ?

    and can anyone explain how maxwell related electricity and magnetism , easily (im in high school)
  2. jcsd
  3. Jul 13, 2012 #2


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  4. Jul 13, 2012 #3

    Claude Bile

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    It can be elegantly explained via relativity;

    From the point of view of electric current, the space between (fixed) positive charges contracts, whereas the density of the negative charge is unchanged. This results in a force that is perpendicular to the direction of the electric current.

  5. Jul 14, 2012 #4


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    As well as Maxwell, there were many others who showed the inter-relation between electricity and magnetism (for example, Faraday). I guess this was the result of both experiment, and the imagination of these people to make the connection between electricity and magnetism. Probably you can go on wikipedia and search these people's names, and it will tell you specific examples of several of the ways in which they related electricity and magnetism.

    About the current in the wire, you should think of currents and charges as sources of the magnetic and electric fields (in a certain sense of the word). Specifically, a charge will cause an electric field to flow into (or out of) the volume enclosing that charge. And a current (through some cross-sectional area) can cause a magnetic field to flow around that area. Also, the electric field depends on changes in the magnetic field and vice-versa, so if the fields are time-dependent, then it is a little more complicated.
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