PHYS208 Fundamentals of Physics II

Answer for Ch. 24, 31P

Consider a gaussian cylinder of radius r and length L. The charge enclosed by the cylinder is given by


and the flux through the tube wall is given by


There is no flux contribution from the endcaps. By Gauss's law, the electric field is then proportional to the distance from the center and to the charge density:


pointing inward.

Outside the cylinder a "line of charge" result is obtained.

Last updated March 4, 1998.
Copyright George Watson, Univ. of Delaware, 1997.