1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Coaxial Cable GRE Question

  1. Sep 15, 2013 #1
    1. The problem statement, all variables and given/known data

    I'm confused why these two currents cancel eachother out perfectly when the distance they are being measured from is closer to the outside current than the inside current...

    Like if the magnetic induction is proportional to the distance from the current,, then wouldn't the outside currents induced magnetic field be a little bit bigger than the inner currents?

    edit: I just realized a potential flaw in my logic... since the outer part goes completely around the inner part,, on average both of the currents are the same distance away from the point P?
  2. jcsd
  3. Sep 15, 2013 #2


    User Avatar
    Science Advisor
    Homework Helper

    Sort of. Just use Ampere's law and the symmetry of the currents.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted