If a charge is located at the center of a spherical volume and the electric flux through the surface of the sphere is φ o, what is the flux through the surface if the radius of the sphere doubles?

The electric flux remains unchanged

Explanation:

From Gauss law the Electric flux is directly proportional to the number of electric field lines passing through a surface. The number of field lines passing through a surface become if the radius is doubled becomes 1/4th that is when radius of the Gaussian surface is doubled, but at the same time, the surface area has increased 4 times , so the electric flux remains unchanged