U q 4丌E0 (7)≠ 推广至任意电荷连续分布的带电体 0()=∑q(F) 4Eo r 带电体 p(r)dr 4E。|r-F0 1 1 [ ] 4 | || N i j i i i j i i q q q q | j πε = > rr rr = + − − U ∑ ∑ rr rr ( ) u r q ϕ ≠ r 推广至任意电荷连续分布的带电体 1 1 0 1 () ( ) 4 | | N N i i i i i q r F r r ϕ ϕ= = πε = = − ∑ ∑ r r r 带电体 0 1 () 4 | r dr r r | ρ πε ′ ′ = ′ − ∫ r r r r