Example: Long Cylindrical Conductor a current I is uniformly distributed over its cross section with a density 丌P2 Figure 9-3 Long cylindrical conductor carrying a current 1
Outside the conductor: B is azimuthal, according to the circuital law 2丌pB=p401.→B 2丌 Inside the conductor 2丌pB=10(mp),→B=0Jp_A0p 2 2丌B 20+×10 10 102030405060 p(millimeters) Figure 9-4 The magnetic induction B as a function of radius for a wire of I millimeter radius carrying a current of 1 ampere