4.将带电量为Q的导体板A移至不带电的导体板B附近,如图所示.两导体板几何-|||-形状完全相同,面积均为S,移近后两导体板距离为 (dlt sqrt (S)), 忽略边缘效应. A B-|||-d-|||-两导体板之间的场强和电势差为 ()-|||-第4题图-|||-(A) =dfrac (Q)(2{varepsilon )_(0)S}, _(AB)=dfrac (Qd)(2{varepsilon )_(0)S} (B) =dfrac (Q)({varepsilon )_(0)S} _(AB)=dfrac (Qd)({varepsilon )_(0)S}-|||-(C) =dfrac (Q)({varepsilon )_(0)S} ,_(AB)=dfrac (Qd)(2{varepsilon )_(0)S} (D) =dfrac (Q)(2{varepsilon )_(0)S}, _(AB)=dfrac (Qd)({e)_(0)S}