## PHYS208 Fundamentals of Physics II

### Hint for Ch. 26, special problem #1

Consider the inner conductor to have linear charge density of +*lambda* and the outer conductor to have -*lambda*.
Evaluate the **E** using a gaussian surface between the two conductors,
and then evaluate the resulting potential difference between the two conductors.
Substitute the parameters stated in the problem into the resulting formula for capacitance.
(*HRW* derives a formula for the capacitance.)

### Hint for Ch. 26, special problem #2

Consider one conductor to have linear charge density of +*lambda* and the other conductor to have -*lambda*.
Employ the superposition theorem to consider the contribution of each line of charge to the total **E**; the contribution from each can be found using the typical configuration of a gaussian cylinder. (See Group Exercise #2.)
Evaluate the resulting potential difference between the two conductors by evaluating the line integral relating **E** to V, and from that a formula for capacitance.

"http://www.physics.udel.edu/~watson/phys208/exercises/hints/0309.html"

Last updated March 8, 1998.

Copyright George Watson, Univ. of Delaware, 1998.