- #1
ELB27
- 117
- 15
Homework Statement
Find the potential on the rim of a uniformly charged disk (radius ##R##, charge density ##\sigma##). [Hint: First show that ##V=k(\sigma R/\pi\epsilon_0)##, for some dimensionless number ##k##, which you can express as an integral. Then evaluate ##k## analytically, if you can, or by computer.]
Homework Equations
[tex]V = \frac{1}{4\pi\epsilon_0} \int \frac{\sigma da}{|\vec{r}-\vec{r'}|}[/tex]
where ##\vec{r}## is the position vector to the point at which the potential is being calculated and ##\vec{r'}## is the position vector of the charge.
The Attempt at a Solution
Well, my first instinct was to jump in and do it brute-force with the above integral but I got stuck with a complicated integral with which even the computer struggled. After that I tried something simple - choose a convenient point on the rim rather than use a general one. Here I got a 0 for ##(R,0)## which doesn't seem right. Now, I didn't use the hint the problem gave me - I can't figure out from where am I supposed to get the ##R## in that equation (the other variables already appear in the formula above). I guess I could try to look for mistakes in the brute-force calculation but I am interested in a more elegant way of doing it which the hint seems to suggest.
Any thoughts on how to use the provided hint to solve this problem?
Thanks in advance!