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: Magnetic field of a Coaxial Cable

  1. Mar 13, 2013 #1
    1. The problem statement, all variables and given/known data

    A long coaxial cable consists of two concentric conductors with dimensions a = 1.20 cm, b = 5.40 cm and c = 7.30 cm. There are equal and opposite currents of 5.00 A in the conductors. Find the magnitude of the magnetic field at a distance of 0.36 cm from the center axis.

    2. Relevant equations


    3. The attempt at a solution

    Far as i can tell because the outer portion of the wire is not enclosed I enclosed for that portion of the problem is 0 so:


    But I'm not getting the right answer.

    Any help would be greatly appreciated

    Attached Files:

    Last edited: Mar 13, 2013
  2. jcsd
  3. Mar 14, 2013 #2


    User Avatar
    2017 Award

    Staff: Mentor

    0.36cm is within the inner cable - just some fraction of the 5A current flow in the inner wire is enclosed in your integral.
    You can assume that (electric) current density is constant in the wire.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted