Electrostatic shell theorem
= Electrostatic shell theorem
{title2=$\mathbf E(r)=Q\mathbf e_r/(4\pi\epsilon_0r^2)$}
Outside a bounded <spherically symmetric charge distribution> in vacuum, the <electric field> is that of a central <point charge> with the same total <electric charge>. With zero <electric potential> at infinity, the exterior <electric potential> is $Q/(4\pi\epsilon_0r)$. A uniform <surface charge> on a <sphere> has zero <electric field> inside.