电磁感应习题三 r>R 时:4=B2xr=A=A一B=m (r<R) B 8丌2R (r>r 8丌 导体上l段内磁能: R 2mrr·l 8丌2R 16兀 the end电磁感应习题三 作者:杨茂田 R r >R 时: = = l内 i l B dl B r I 2 0 I = 0 r I B 0 2 = r r = = 2 2 B wm 2 2 4 2 0 8 r R I 2 2 2 0 1 8 r I (r R) (r R) 导体上 l 段内磁能: = V Wm wm dV r dV R I = 2 2 4 2 0 8 2 rdrl 0 2 16 I l Wm = ( the end ) I 0 R