Current through a loop

As we discussed earlier, our canonical example with be the long straight wire. In this case, the wire is a bit thick, so that we can investigate what happens inside the wire as well. That's a tough job with Biot-Savart. We will use Ampere's law to find the magnetic field both inside and outside the thick wire. On this page, we will focus on the right-hand side of Ampere's law, namely, the current through our Amperian loop.