How Does a Magnetic Field Influence Electron Energy Levels?

[captainjack2000]

Homework Statement

Considering only orbital angular momentum, estimate the energy level separation between electron states in a magnetic field of 1 Tesla applied along the z direction.

Homework Equations

I am confused by how to even start this question! Isn't orbital angular momentum just integer*h / (2Pi) ??

Could someone please point in the right direction. Thanks

The Attempt at a Solution

 

[nickjer]

I suggest first writing down the perturbation for a weak magnetic field. Then finding the first order shift in energy for the unperturbed states: $|l,m\rangle$.