Question

Apply gauss theorem to show that for a spherical shell, the electric field inside the shell vanishes whereas outside it, the field is as if all the charge has been concentrated at the centre.

Answer 1

Answer:

Consider a thin spherical shell of radius R with a positive charge q distributed uniformly on the surface. As the charge is uniformly distributed, the electric field is symmetrical and directed radially outward (positive charge) in all directions. The magnitude of electric field is the same at all points that are equidistant from the shell. All such points lie on a sphere. So the symmetry here is spherical symmetry. Hence we shall use a spherical Gaussian surface to find the electric flux and hence the magnitude of electric field at a point inside and outside of the charged shell.