Electric Flux

Suppose a point charge is located at the center of a spherical surface. The electric field at the surface of the sphere and the total flux through the sphere are determined. Now the radius of the sphere is halved. What happens to the flux through the sphere and the magnitude of the electric field at the surface of the sphere?

• The flux and field both increase.

• The flux and field both decrease.

• The flux increases, and the field decreases.

• The flux decreases, and the field increases.

• The flux remains the same, and the field increases.

If the net flux through a gaussian surface is zero, the following four statements could be true. Which of the statements must be true?

(a) There are no charges inside the surface. (b) The net charge inside the

surface is zero. (c) The electric field is zero everywhere on the surface.

(d) The number of electric field lines entering the surface equals the number leaving the surface.

• There are no charges inside the surface.

• The net charge inside the surface is zero.

• The electric field is zero everywhere on the surface.

• The number of electric field lines entering the surface equals the number leaving the surface.