7) a long straight wire of radius 1.00x10-3 m (1 mm) carries uniform current density j such that the magnetic field at the edge of the wire is 10-5 t. at what distances from the center of the wire is the magnetic field equal to 5x10-6 t? a) 0.5 and 2 mm. b) 2 mm only. c) 0.5 mm only. d) 0.25 and 2 mm. e) 0.25 mm and 2 mm