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Homework Help: Magentic induction and shielding

  1. Jul 16, 2007 #1

    This happens when the ferro-magnetic material is placed near to the magnet. (call this induced magnetism)


    if the bar shape ferro-magnetic material's length is compressed into as thin as a sheet of iron,


    Electromagnetic shielding occurs.


    In the first situation, an iron pin will be attracted by the induced iron, but in the second situation, the iron pin will not be attracted.

    I do not understand why will there be two occcurance, and how to classify any situation to know which will occur.
  2. jcsd
  3. Jul 16, 2007 #2


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    What "pin" are you talking about? In the first case you have a bar of iron that is attracted to the magnet. In the second you flatten the iron into a sheet which will also be attracted to the magnet. I see no "pin" in either case.
  4. Jul 16, 2007 #3
    the pin is not in the picture
    imagine a pin approach the iron bar, or sheet in both cases, from the right.

    From what i was told, the magnetic field will flow through the iron bar, therefore magnetising it. (so the pin will be attracted to the iron bar)

    But, in the case of a the iron sheet, the magnetic field is diverted(shielding), and anything belhind will not experience magnetism from the magnet. (the pin does not feels any attraction)

    what difference is there between a sheet and a bar magnet? isnt it just the 'length' of that piece of iron? why are there 2 different results?
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