In an electricity demonstration at the Deutsches Museum in Munich, Germany, a person sits inside a metal sphere of radius 0.90 m
. Charge is applied to the sphere until the magnitude of the electric field on the outside surface of the sphere is 3.0×105N/C. When the demonstration is over, the person climbs out unharmed. During the demonstration, what is the magnitude of the electric field inside the sphere?
As the sphere is metallic, the electrical charges are distributed on its surface, as far away as possible from each other.
If we apply Gauss's law, as the charge is on the surface, when drawing a spherical Gaussian surface, we see that there is no charge inside, therefore there is no electric field inside the metallic sphere.