# Electric potential at the charge

1. Oct 17, 2011

### berra

1. The problem statement, all variables and given/known data
What should I do when I calculate the potential of point charges at the point of one of the point charges?

2. Relevant equations
The definition of a potential from point charges are:
$$\phi(\textbf{r}) = (4\pi \epsilon_0)^{-1}\sum_{i}[q_i |\textbf{r}-\textbf{r}_{q_i}|^{-1}] + C$$
3. The attempt at a solution
Setting $q_i |\textbf{r}-\textbf{r}_{q_i}|^{-1}=0$ when $\textbf{r}-\textbf{r}_{q_i}=\textbf{0}$. Haven't seen this anywhere in the lecture material though, but I am guessing that is what one should do. If so, what is the "real" definition of the potential?

2. Oct 17, 2011

### vela

Staff Emeritus
The potential diverges as the location of the point charges. It's not defined there.