磁介质 例2一均匀磁化磁介质球,求球心处B =M.1·sinb= Msin e dn=i' rdo= mrsin ede M dB′=r2a d 2 R 2-+ uo(rsin 8) mrsin gde 2 R sin ede B Sindo= (COS6-1)dc06=/0 与A同' 1 sin sin ' ' sin i M M dI i Rd MR d      =   = = = 例2. ' 一均匀磁化磁介质球，求球心处B z 2 0 3 2 2 2 2 0 3 0 3 ' ' 2 ( ) ( sin ) sin 2 sin 2 r dI dB z r R MR d R M d         = + = = 0 0 3 2 0 0 0 2 ' sin (cos 1) cos 2 2 3 M M B d d M M      = = − =        与 同向