10-5 如图所示,两个同心球壳,内球壳半径为R1,均匀带有电量Q;外球壳半径为R2,壳-|||-的厚度忽略,原先不带电,但与地相连接。设地为电势零点,则在内球壳里面,距离球心为r处的-|||-P点的电场强度大小及电势分别为 () 。-|||-(A) =0, =dfrac (Q)(4pi {varepsilon )_(0)(R)_(1)} (B) =0, =dfrac (Q)(4pi {varepsilon )_(0)}(dfrac (1)({R)_(1)}-dfrac (1)({R)_(2)})-|||-(C) =dfrac (Q)(4pi {varepsilon )^circ (r)^2} =dfrac (Q)(4pi {varepsilon )^circ r} (D) =dfrac (Q)(4pi {varepsilon )^circ (r)^2} =dfrac (Q)(4pi {varepsilon )_(0)(R)_(1)}-|||-9-|||-7-|||-R2 R-|||-r P-|||-习题 10-5 图