a) Observe Figure 1a below. If a current, I, flows in an infinitely long conducting wire, the magnetic flux density, B, is defined as a function of distance r, from the wire. It is assumed that r is much greater than the radius of the wire. Derive the expression for the flux density, B, at a point r from an infinitesimally thin wire that is infinitely long. Show all of your workings.

a) Observe Figure 1a below. If a current, I, flows in an infinitely long conducting wire, the magnetic flux density, B, is defined as a function of distance r, from the wire. It is assumed that r is much greater than the radius of the wire. Derive the expression for the flux density, B, at a point r from an infinitesimally thin wire that is infinitely long. Show all of your workings.