1. The problem statement, all variables and given/known data Attached. 2. Relevant equations 3. The attempt at a solution I've been meaning to do this question for a while now but don't have much of a strategy. I was informed that the ribbon should be treated as a series of parallel wires. The magnetic field at an arbitrary point P from a wire with a current flowing through it can be given by the biot-savart law. The magnetic field at a point P a distance r away from a single long wire is thus given by: Now, I have the suspicion that, since the ribbon comprises a whole bunch of wires, the total magnetic field due to the ribbon would simply be the result of an integration over the width of the ribbon. However I am having difficulty in figuring out the initial set up of the integral., and an appropriate parameterisation (if that is at all needed).