Why is that amperes circuital law gives the same magnetic field around a finite legnth of wrie as if it is an infintie legnth of wire? By biot-savarts law we know that for a finite length of wire magnetic field is μ i ( cos θ1 - cos θ2)/ 2∏r I searched this question in google and one of the answer was that magnetic field will not be tangential to the circular loop we imagine around the wire. So when we integrate magnetic field cannot be calculated But thats wrong isnt it? By biot-savarts law we see that magnetic field is tangential around the wire along the circular loop with the constatn value as given above. So we can integrate it and find the magnetic field using amperes law But answer does not come. Why? Sorry if it ahs been asked again. Give me the link if it has been. Thank you!