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Induced current in magnet (what would happen if...)

  1. Aug 12, 2017 #1
    1. The problem statement, all variables and given/known data
    Screen Shot 2017-08-12 at 10.54.54 PM.png

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    3. The attempt at a solution

    I'm having a lot of trouble understanding induced magnetic fields. I was wondering if someone can explain it for me and confirm if I have the right answers?

    a) I labelled it [North | South], and the direction of the current is going counterclockwise
    b) If the direction of motion of the magnet is reversed, the direction of the current is reversed (in this case it would go clockwise and [South | North] ). The magnetic field produced by the current will oppose the change that produces the current and pull back on the bar magnet, resisting the inducing action.
    c) If the magnet is moved more quickly, the coils will rotate faster and a greater current will be created. (Im not sure what would happen to the magnetic field? would it be a stronger opposing force?)
    d) Im completely lost at this last question... Would the induced current be greater because there is a constant change in direction/speed? Would the magnetic field be greater because it is constantly changing?

    This is just an introductory course so I have not learned about Farraday's law (only Lenz's law). Any insight is appreciated please and thanks!

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    Last edited by a moderator: Aug 13, 2017
  2. jcsd
  3. Aug 13, 2017 #2


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    Not quite sure what you mean by counterclockwise in this context.
    Are you saying it would be left to right in the straight portion and right to left (as viewed in the diagram) in the coil?
    That doesn't sound right to me.
  4. Aug 13, 2017 #3
    I meant it like this picture right here how it's coiled. Am I right?
    And am I right about the other questions?

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  5. Aug 13, 2017 #4


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    The coils don't move.
    I'm not sure what they after either. Maybe something about resonance?
    Ok. The problem with just saying "counterclockwise", meaning the direction the current flows around the rod, is that it depends which end of the rod you are looking from.
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