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Brewer
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Homework Statement
Using Ampere's circuital law, or otherwise, find the magnetic field B a distance r away from the axis of a thin walled circular hollow conductor of radius a and carrying a current I.
Homework Equations
[tex]\oint_L B\cdot dL = \mu_0I_{enclosed}[/tex]
The Attempt at a Solution
So far I have said:
the conductor is a hoop. As a result inside the hoop (i.e. r<a) B=0 as [tex]I_{enc}[/tex]=0.
However I am confused as to what line I should take to work out B when r>a. Does the system act like a long straight line (albeit in a circle) and the B-field is a loop around the hoop (cancelling out in the middle, and thus obtaining the same result for r<a), or is it some other shape all together?