The electric field outside a sphere with total charge Q distributed with spherical symmetry can be found immediately from Gauss's law. In MKS using a spherical surface,

where is the perittivity of free space, so

where is a unit radial vector. This is the same result that would be obtained from a full-blown integration of Coulomb's law,and is analogous to the result that the gravitational force from a sphere is equal to the force from a point mass equal to the total mass of the sphere and located at its center.