

Looking back at
Electric Flux
In the following questions, a Gaussian cylinder with
radius a and length l is placed in various electric fields. The end
caps are labeled A and C and the side surface is labeled B. In each
case, base your answers about the net flux on qualitative arguments about
the magnitude of the flux.
a) The Gaussian cylinder is in a uniform electric
field of magnitude E which is aligned with the cylinderís axis.

Find the sign and magnitude of the flux through surface
A, surface B, and surface C.

Is the net flux through the entire Gaussian surface
positive, negative or zero?
b) The Gaussian cylinder encloses a negative charge.
(The field from the previous part has been removed.)

Find the sign of the flux through surface A, surface
B, and surface C.

Is the net flux through the entire Gaussian surface
positive, negative or zero?
c) The Gaussian cylinder encloses opposite charges
of equal magnitude. (The charges are on the axis of the cylinder and equidistant
from the center.)

Find the sign of the flux through surface A, surface
B, and surface C.

Is the net flux through the entire Gaussian surface
positive, negative or zero?
d) A positive charge is located above the Gaussian
cylinder.

Find the sign of the flux through surface A, surface
B, and surface C.

Is the net flux through the entire Gaussian surface
positive, negative or zero?

