Comparison of Ampere´s circuital law (ACL) and the law of Biot-Savart (LBS)

Ampere´s circuital law (ACL) and the law of Biot-Savart (LBS) are applied to the computation of the magnetic flux density at the center of the square loop. The results are compared and some common misunderstandings of students are clarified. It is seen that LBS is general and applies to closed or open circuits. In the case of open circuits, care must be exercised in applying the ACL. Here, two choices present themselves; one is to use a modified form of ACL appropriate to the problem at hand and the second is to use ACL in its generalized form, which takes into account the inevitable charge accumulations