Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Faraday's Law vs Kirchoff's Rule in circuit - nonconservative fields

  1. Aug 9, 2012 #1
    I am trying to compare the "relation" conventions used in Kirchoff's Loop Rule with Faraday's Loop Rule.

    Kirchoff

    Please go to this MIT OCW link on Kirchoff's Rule and go to page 8/29. Of the four boxes, I would like to point this one

    K_E.jpg

    Note that the yellow electric field was added by me. This picture also follows the integral

    [tex]-\int_{a}^{b} \mathbf{E}\cdot d\mathbf{s} = \int_{a}^{b} -Eds = \Delta V = \varepsilon = -IR [/tex]

    Since ds and E are parallel.

    Nonconservative Fields with Faraday

    Now if I go to this video (I take you to EXACTLY where I want you to watch, so don't worry about searching which part of the video does this happen)

    http://www.youtube.com/watch?v=UpO6t00bPb8#t=10m22s

    Now quoting him

    Note that his circuit arrangement is exactly like mine, he went from a high potential to a low potential. The current, electric field in the wire, and the travelling direction are all the same, yet he gets +IR instead of -IR

    is he still using this "E dot dl" [tex]-\int_{a}^{b} \mathbf{E}\cdot d\mathbf{s}= \Delta V[/tex]? How does Faraday's Law apply for non-closed paths? Because it seems like Lewin is using [tex]\int_{a}^{b} \mathbf{E}\cdot d\mathbf{s}= \Delta V[/tex] (no minus sign)

    The same confusion goes when he talks about the electric field in the battery.

    Could someone please clarify for me? Thank you
     
  2. jcsd
  3. Aug 10, 2012 #2
  4. Aug 10, 2012 #3
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Faraday's Law vs Kirchoff's Rule in circuit - nonconservative fields
  1. Kirchoff's law? (Replies: 5)

Loading...