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How to identify a magnet from a metal bar

  1. Dec 5, 2006 #1
    I have what is hopefully a quick question. Using only an unmarked magnetic bar and an identical metal bar, suggest a way to find out which is the magnet and which is the metal bar. This is supposed to be in a room with nothing but these two materials. Any help is greatly appreciated!
  2. jcsd
  3. Dec 5, 2006 #2


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    Hint: the middle of the bar magnet is not "magnetized".

  4. Dec 5, 2006 #3
    Okay... so if you have the metal bar and move one end of the magnetic bar along it, there should always be an attraction/repulsion between the two. But if you do this vice versa, moving hte metal bar along the magnet, then once you get to the middle there should be no attraction/repulsion at all?
  5. Dec 5, 2006 #4


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    Very close! But one tiny detail is wrong.

    It's only one of those two possibilities. Which one?
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