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B Electromagnet and a current carrying wire

  1. Dec 27, 2017 #1
    Hi,
    My understanding of an electromagnet is that it is a material with low susceptibility and high permeability, i.e. the magnetic field is not permanent but in the application of a current then the material gets a large magnetic field. In the application of a current the spins of the electrons in the material align in the same direction so the material gets a net "magnetic moment" or magnetic field. I have read on Wikipedia that the magnetic core "focuses" the field caused by the current so the field strength increases by thousands of times. I also know that the current is caused by an electric field drawing the loose valance electrons forward to make a flow of electricity. So my question is this: if you had a hypothetical wire that had in its interior a vacuum, and a shell that no electrons could escape from, could this wire, if wrapped around a material with
    high permeability, generate a magnetic field? I am not sure if the electrons have to escape the wire and go into the magnetic core for the material to get a magnetic field.
     
  2. jcsd
  3. Dec 27, 2017 #2

    davenn

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    Science Advisor
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    2017 Award

    What do you mean by this ??

    of course not .... that doesn't happen in a normal electro-magnet
    Also the wire of the coil is insulated otherwise the turns of the coil would short circuit
     
  4. Dec 27, 2017 #3

    anorlunda

    Staff: Mentor

    Do you mean a wire with a vacuum-filled hollow core, like a hollow cylinder? There is essentially no difference between that and a regular wire.
     
    Last edited: Dec 28, 2017
  5. Dec 28, 2017 #4
    Yea that's what I mean.
     
  6. Dec 28, 2017 #5

    anorlunda

    Staff: Mentor

    No, it refers to the type of answer you get. An I answer is likely mathematical. A B answer is mostly in words. I'm going to change this thread to B for you and I cleaned up the posts. Hopefully that might get some good answers for you.
     
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