A point charge +Q is located on the x axis at x = a,and a second point charge -Q is located on the x axis at x = -a.A Gaussian surface with radius r = 2a is centered at the origin.The flux through this Gaussian surface is
A)zero because the negative flux over one hemisphere is equal to the positive flux over the other.
B)greater than zero.
C)zero because at every point on the surface the electric field has no component perpendicular to the surface.
D)zero because the electric field is zero at every point on the surface.
E)none of the above.

Question

Quizplus · Accepted Answer

By symmetry, the electric field at any point on the Gaussian surface will have the same magnitude and direction for opposite points on the surface. Therefore, the flux over one hemisphere will be equal and opposite to the flux over the other hemisphere, resulting in a total flux of zero.

A Point Charge +Q Is Located on the X Axis