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Magnetic fields etc

  1. Feb 13, 2007 #1
    1. The problem statement, all variables and given/known data

    Not too difficult really, but I'm not understanding why two wires with identical currents running through them will move together. The question is, 'what happens when two parallel wires carry identical currents in oppsite directions?' But I dont understand what happens when they carry them in the same direction, so can't atempt this question.

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Feb 13, 2007 #2


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    Staff: Mentor

    Thread moved from Advanced Physics to Intro Physics.

    Start by drawing the magnetic field that circulates around the wire axis for each wire. Now, the electrons that are moving in a nearby wire will be affected by that circulating magnetic field in what way? Remember to use the right-hand rule to figure out the direction of the force on the moving electron charges in the magnetic field.
  4. Feb 13, 2007 #3


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    Gold Member

    The following will probably help you:
    1)Ampere`s law
    2)Laplace force + Right-hand rule
  5. Feb 13, 2007 #4
    http://www.physics4students.com/pages/dataDump/rightHandRule.jpg [Broken]
    Take a look at the top picture. The magnetic field at a point to the right of the wire points into the screen. A bar magnet would have its north pole into the screen and its south pole out of the screen. If an identical second wire is placed to the right of that, its field would point into the screen. A bar magnet to the left of the second wire would have its south pole into the screen and its north pole out of the screen. Now we have 2 magnets arranged north-south and south-north, which will attract each other
    Last edited by a moderator: May 2, 2017
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