The Ampere's Circuital law states
$$\oint B\cdot d\ell~=~ \mu_0I$$
We can use it to derive the magnetic field of an infinitely long current carrying wire easily. My question is, why does the wire need to be infinitely long? I know it has something to do with $B$ being constant and tangential to the loop at every point for easy evaluation of the integral, but I can't find an explanation to my question.
No comments:
Post a Comment