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Homework Help: What is the direction of the current in the loop?

  1. Apr 10, 2009 #1
    A rectangular loop of wire is placed above a long straight wire with decreasing current. If the current in the wire moves from as specified by the diagram I drew below what will be the direction of current in the loop. I thought that the current in the loop would move counterclockwise. I thought that the force created in the loop would be opposite that of the wire. Since the force would be in different directions then the current had to be in the opposite direction, which is counter clockwise. Am I thinking about this concept correctly or should the current be in the clockwise direction. What kind of throws me of is that it says the current is decreasing. I am not exactly sure how that will affect the current in the loop. Thank you very much.


    (Loop-4 sides)


    ____>______>____>___ (wire, > is the direction of current)
  2. jcsd
  3. Apr 10, 2009 #2


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    Staff Emeritus
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    Homework Helper

    The thing to look up in your text book is magnetic induction, or Faraday's law of induction, or induced EMF. The discussion should also mention Lenz's Law, which will tell you the direction of the current.

    The fact that the magnetic field is changing is the key to this one.
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