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Homework Help: How do I use right hand rule to determine the current created to oppose flux change?

  1. May 3, 2012 #1
    Hey guys,
    I have a simple conceptual question: Lets say I'm moving a loop of wire into a constant magnetic field that points into the page. The wire needs to create a magnetic field out of the page to oppose this previous change in flux. The typical question would be which direction does the current flow? I know about the right hand rule where you wrap your hand around the wire and let thumb point in the direction of the current. But the magnetic field created by a wire is such that it wraps around the wire, so Im not sure from which side i have to wrap my hands around the loop to represent the field created?

    An example of an answer to clarify my question (just guessing btw): the direction of the magnetic field created to oppose the change in flux is represented by the direction your fingers point on the INSIDE of the loop.

    Thanks in advance for your efforts.
  2. jcsd
  3. May 3, 2012 #2
    Re: How do I use right hand rule to determine the current created to oppose flux chan

    Your example of an answer is actually the correct way to look at it. The ambient field points into the page, so according to Lenz's law, the induced current will create a field out of the page.

    If you "grab" the ring, and let your thumb rest along the ring, the tips of your fingers go around the outside ring, but when they reach the inside of the ring, they point out of the page, toward you, so the current is going counterclockwise.
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