# Modern physics: Atomic Structure

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1. Sep 21, 2015

### ira

1. The problem statement, all variables and given/known data
If we take the average radius of the electron wave function in the ground state of hydrogen to be the Bohr radius, calculate the average potential energy of the electron due to the Coulomb interaction with the nucleus. State answer in eV.

2. Relevant equations
I think the relevant equation is V(x)= -(e^2) / [ 4(pi)(epsilon naught)(delta x) ]

3. The attempt at a solution

1/[4(pi)(epsilon naught)] = constant = 8.9876x10^6
The Bohr radius= 5.29x10^-11 m <--- (is this delta x?)
e = 0.511 MeV =5.11x10^5 eV (is this even correct? does 'e' mean the electron charge or mass?)

V(x)= [[-(0.511)^2] . (9.9876x10^6) ] / 5.29x10^-11
=4.436x10^28

As you can see I have many doubts. Hope any of you physics genius can help!

2. Sep 21, 2015

### Staff: Mentor

What do you expect in a formula for the potential of a charged object in the field of another charged object?

Just work with units, then you'll see what went wrong.

3. Sep 21, 2015

### ira

So, does e mean the mass of electron?

4. Sep 22, 2015

### Staff: Mentor

Do the units match if you plug in a mass?