e dt 42 4πr2 1。=ja42=-02e ◆I=I。+I:=0 →=0 ENDt eQ t q I εγ ε γ c d d − =−= t e r Q r q D εγ− == 2 2 4π 4π t e r Qj ε γ ε γ − −=d 2 4π 1 t eQrjI ε γ ε γ − −== 2 dd 4π = + III dc = 0 H = 0 c I d I END