Question

A thin metallic spherical shell of radius 49.6 cm has a total charge of 5.55 μC uniformly distributed on it. At the center of the shell is placed a point charge of 1.03 μC. What is the electric field at a distance of 12.4 cm from the center of the spherical shell?

Answer 1

Consider a spherical gaussian surface of radius 12.4 cm cocentric with the given spherical shell and using symmetry arguments prove that E field is same at all points on the gaussian surface and is radial , apply gauss law. The charge enclosed in the surface will include only 1.03 micro coulomb and not that 5.55 situated outside the surface on the sphere.