Homework 2
PHYSICS 5C
Homework 2
Due in class, Friday October 16

Field of a charged ring.
A ring shaped conductor with radius a carries a total charge Q uniformly
distributed around it, see figure. Find the electric field at a point, P, that
lies on the axis of the ring at a distance x from its center. Show that for
, the magnitude of the field increases linearly with x and that for
, the field is the same as that of a point charge Q located at the
center of the ring. Sketch the magnitude of the electric field as a function of
x.

Field of a uniformly charged sphere.
Positive electric charge Q is uniformly distributed throughout the volume of
an insulating sphere of
radius R. What is the direction of the electric field? Find the magnitude
of the electric field at a point P a distance r from the center, both for
r < R and r > R. Show that for r > R, the field
is the same as if all the charge were concentrated at the center of the sphere.
Hint: Use Gauss' theorem.
Young and Freedman
2246, 2252
Q232
235, 236, 2315, 2328, 2344
Main Page for Physics 5C
Peter Young
Thu Oct 2 21:32:53 PDT 1997