PROBLEM 2 (25 points)
The Hamiltonian for an electron in a hydrogen atom subject to a constant magnetic field \( \mathbf{B} \) is given by
\[
H=\frac{\mathbf{p}^{2}}{2 m_{e}}-\frac{e^{2}}{4 \pi \varepsilon_{0} r}+\frac{e}{2 m_{e}}(\mathbf{L}+2 \mathbf{S}) \cdot \mathbf{B}
\]
where \( \mathbf{L} \) and \( \mathbf{S} \) are the angular momentum and spin operators respectivelyr. Assume the magnetic field points in the z -direction.
(a) How many distinct energy levels will the \( n=3 \) state have?
(b) Consider the line corresponding to the transition \( (n=3, l=2) \rightarrow(n=2, l=1) \). Find the energy of the emitted photons ( \( \hbar \omega=\Delta E \), with \( \Delta E= \) the energy difference between initial and final state), assuming the possible transitions are constrained by the selection rule \( \Delta m=0, \pm 1 \).