Solution
= Solution
The <spherical harmonic> is also an <eigenfunction> of the $z$ component of <orbital angular momentum>:
$$
\boxed{\hat l_zY_{lm}=mY_{lm},\qquad m=-l,-l+1,\ldots,l.}
$$
These are <atomic units>; restoring units gives $m\hbar$. The integer $m$ is the <magnetic quantum number>.