(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A coaxial cable of length l, has a thin wall cylindrical inner conductor of radius a carrying current I. All current returns along the outer conductor whose inner radius is b.

Assuming that the current flows only in a thin layer on each conductor, determine the magnitude and direction of the magnetic induction B at radius r.

a) when r<a

b) when a<r<b

c) when r>b

2. Relevant equations

[tex]\oint(B.dl) = \mu0 I[/tex]

3. The attempt at a solution

Ive just started studying magnetostatics and am a little bit confused. I think using Ampere's Law in each of the three cases is the right thing to do, but I am unsure on what the value for I is in each case.

For part a), i think B * 2 * pi * r = [tex]\mu[/tex]0 * I

but then i dont know how it differs for part b).

Thanks for any help

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# The Magnetic Field of Coaxial Cables

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