For a mass M kept at the centre of a cube of side ‘a’, the flux of gravitational field passing through its sides is 4π GM. how ?? Share with your friends Share 3 Ved Prakash Lakhera answered this The gravitational field at the centre of a cube ofside a is given by, E=GMa2Now constructing Gaussian surface around the cube of radius a, we get, φ=∮E×dS=E×4πa2=GMa2×4πa2=4π×GM. 17 View Full Answer