Problem 3.41

A point electric dipole with a moment \(\mathbf{p}\) is placed in the external uniform electric field whose strength equals \(\mathbf{E}_ {0}\). with \(\mathbf{p} \uparrow \uparrow \mathbf{E}_ {0} .\) In this case one of the equipotential surfaces enclosing the dipole forms a sphere. Find the radius of this sphere.