- #1
mmh37
- 59
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Hey everyone,
I have failed to show that the magnetic flux outside a cylindrical conductor is zero.
The problem goes like this:
a coaxial cable consists of a solid inner cylindrical conductor of radius a and an outer cylindrical conductor of inner and outer radius b and c. Distributed currents of equal magnitude I flow in opposite directions in the two conductors. Derive expressions for the magnetic flux density B(r) for each of these regions
1) 0<r <a
by amperes law I showed: [tex] B = \frac {K *l*r} {2*pi*a^2} [/tex]
where K is the permeability of free space, don't know how to write that with latex
2) a<r<b
again by amperes law: [tex] B = \frac {K *l} {2*pi*r} [/tex]
3) b<r<c
again by amperes law: [tex] B = \frac {K *l*(r^2-b^2)} {2*pi*r*(c^2-b^2)} [/tex]
4) c<r
I got stuck here, surely it must be zero...but how can that be shown?
thanks for your help - it's very much appreciated
I have failed to show that the magnetic flux outside a cylindrical conductor is zero.
The problem goes like this:
a coaxial cable consists of a solid inner cylindrical conductor of radius a and an outer cylindrical conductor of inner and outer radius b and c. Distributed currents of equal magnitude I flow in opposite directions in the two conductors. Derive expressions for the magnetic flux density B(r) for each of these regions
1) 0<r <a
by amperes law I showed: [tex] B = \frac {K *l*r} {2*pi*a^2} [/tex]
where K is the permeability of free space, don't know how to write that with latex
2) a<r<b
again by amperes law: [tex] B = \frac {K *l} {2*pi*r} [/tex]
3) b<r<c
again by amperes law: [tex] B = \frac {K *l*(r^2-b^2)} {2*pi*r*(c^2-b^2)} [/tex]
4) c<r
I got stuck here, surely it must be zero...but how can that be shown?
thanks for your help - it's very much appreciated