[QUE/EM-04005] EM-PROBLEM

A conducting spherical shell of radius \(a\) is placed in a uniform field \(vec{E}\). Show that the force tending to separate two halves of the sphere across a diametrical plane perpendicular to \(\vec{E}\) is given by \[ F = \frac{9}{4}\pi \epsilon_0a^2 E^2.\]

Panofsky and Philips