What is the Characteristic Electric Field in an Atom?

[silimay]

Homework Statement

Using the values of $$\hbar$$, the electron mass and the electron charge, find the characteristic value of the electric field in an atom, in statvolts / cm (cgs).

Homework Equations

$$r_n = \frac{n^2 h^2}{4 {\pi}^2 m e^2}$$

The Attempt at a Solution

So I wasn't really sure what to do with this problem...would you just try to find the E field classically? I tried doing

$$E = \frac{e}{r^2}$$

$$E = \frac{\pi^2 m ^2 e ^ 5}{n^2 \hbar^4}$$

But that doesn't look right to me...esp the units...

 

[dextercioby]

Is r_{n} expressed in cgs units ? If so, then it's okay. E_{at} in the Bohr model is good.