Question

Two sphere's are isolated from each other. They each have an identical net positive charge and have the same radius, however, one sphere is solid and insulating, while the other is a hollow conducting sphere whose charge is uniformly distributed.
For which sphere is the electric field the greatest distance $x$ from the center of the spheres?
Assume $x$ is less than the radius of the spheres.

• A. The conducting hollow sphere has a greater E-field.
• B. The insulating solid sphere has a greater E field.
• C. Both spheres have the same E field.
• D. Neither sphere would cause there to be an Electric field.

Answer 1

The correct option is B The insulating solid sphere has a greater E field.

The charge in a conducting hollow sphere resides on the surface only. Hence on applying Gauss Law on a spherical surface enclosed in the sphere, we get electric field to be zero inside it.

For a solid insulating sphere with uniform charge distribution, finite electric field exists in the sphere.

Hence correct answer is option B.