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I Voltages in an induced current

  1. Nov 18, 2016 #1
    I've been messing around with ampere's and faraday's laws as we have recently been applying them in undergrad level physics. I'm confused as to how voltage fits in with these laws when used for a solenoid inducing a current in a material placed inside the solenoid. I know that the induced current will flow in a circular motion and the voltage is determined by change in magnetic flux over time. But at a specific radius that the current is flowing around within the solenoid, there should be a constant amount of changing flux along the perimeter of the same radius. So there is obviously something I am missing, but to me this would mean there is constant voltage along the circular path that the current flows which makes no sense to me since the current would usually flow from high to low voltage.

    How can voltage be easily visualized in this situation? Or have I assumed anything incorrectly?
  2. jcsd
  3. Nov 19, 2016 #2

    Simon Bridge

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    Welcome to PF;
    The voltage is the difference in electric potential energy between two points.
    Current naturally flows between points where there is a non-zero potential difference.
    But that is not the only way to move charges about.

    Just like masses naturally roll down between places where there is a gravitational potential difference ... but that is not the only way to move masses around.
  4. Nov 19, 2016 #3
    Hmmmmm ok so does that then mean lens's/faraday's law (V = - change in flux / change in time) does not apply to this situation? if anything I now have more questions than I started with haha
  5. Jan 5, 2017 #4


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    It certainly does apply !
    Good condition for learning opportunities :smile:. Work out such questions a bit and post when stuck !

    The underlying equation is one of the maxwell equations: a changing magnetic field causes an electric field. Then the motion of charge carriers follows from the Lorentz force, equally fundamental.
  6. Jan 5, 2017 #5
    AHH ok I think the thing I was missing is the lorentz force to enable a better visualisation of voltage in the coil, I think from this i can figure out roughly what a graph of voltage over the cross section of the coil would look like I hope. Thankyou!
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