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**Ampere's Circuital Law**sort of fishy. I don't understand what the actual theory proposes. And the loop that should be taken into consideration adds much to the confusion. How should we select the loop?

And in the case of a long wire we find the magnetic field around it by applying ##B.2\pi r= \mu_o i_{enc}##. So how do we find the magnetic field due to a short wire (which is not long or infinitely long)?

Using Biot Savart Law we find the magnetic field due to a short wire as ##\mu_o/4\pi r (cos\theta_1-cos\theta_2)##

where ##cos\theta_1## and ##cos\theta_2## are the angles between the length vector (towards the direction of current) and the position vector at the extreme ends.