2.如图所示,半径为R的均匀带电球面,总电荷为Q,设无穷远处的电-|||-势为零,则球内距离球心为r的P点处的电场强度的大小和电势为:-|||-(A) E=0, =dfrac (Q)(4pi {varepsilon )_(0)R}-|||-(B) E=0, =dfrac (Q)(4pi {varepsilon )_(0)r}-|||-(C) =dfrac (Q)(4pi {varepsilon )_(0)(r)^2} . =dfrac (Q)(4pi {varepsilon )_(0)r}-|||-(D) =dfrac (Q)(4pi {varepsilon )_(0)(r)^2} . =dfrac (Q)(4pi {varepsilon )_(0)R}-|||-Q-|||-O r-|||-R P