Past exam of the physics course of the year 4 of the natural sciences course of the University of Cambridge / 2016 / Paper 1 / Section B / B1 / a

In the paper's convention $\mathbf{J}$ is measured in units of $\hslash$, and $g$ is dimensionless. For $m=-J,-J+1,\dots ,J$, the magnetic moment and its Zeeman energy areIf $\mathbf{J}$ instead denotes dimensional angular momentum, its coefficient must contain $1/\hslash$. This resolves the units of the printed moment formula.