# Homework Help: Magnetic moment of proton and electron of H-atom in ground state L=0

1. Mar 7, 2012

### lquinnl

1. The problem statement, all variables and given/known data

Consider the Hydrogen atom in a magnetic field of 2T. If the atom is in its ground state (orbital angular momentum L=0):
(a) Write down the magnetic moments of the proton and the spinning electron. [1]

2. Relevant equations

I am aware that the magnetic moment μ = (q/2m)L

3. The attempt at a solution

but because L=0 this means that μ=0 for both the proton and the electron, which doesn't seem to me to be a valid answer.

Is this the correct way to be attacking this problem or am i missing something?

Any help with pointing me in the right direction would be much appreciated.

Thanks.

Last edited: Mar 7, 2012
2. Mar 7, 2012

### dextercioby

I think it asks for the expectation value of the magnetic moment operator in the fundamental state (1s).

3. Mar 8, 2012

### lquinnl

Thanks for the help, but I've looked at it some more alongside my lecture notes and I think what they want is:

$\mu^{spin} = -2 \frac{e\hbar}{2m_{e}}m_{s}$

for the electron, and for the proton:

$\mu = -2.79 \frac{e\hbar}{2m_{p}}m_{s}$

Do you think that seems reasonable? Im gonna ask the lecturer tomorrow if it is the expectation value he wants or not.

Thanks again for the feedback!