A flat circular coil with 107 turns, a radius of 4.32 10-2 m, and a resistance of 0.472 ? is exposed to an external magnetic field that is directed perpendicular to the plane of the coil. The magnitude of the external magnetic field is changing at a rate of ?B/?t = 0.816 T/s, thereby inducing a current in the coil. Find the magnitude of the magnetic field at the center of the coil that is produced by the induced current.