An electron moving around the nucleus with an angular momentum L has a magnetic moment

An electron moving around the nucleus has a magnetic moment given by $\mu =\frac{e}{2m}L$

where, L is the magnitude of the angular momentum of the circulating electron around the nucleus. The smallest value of $\mu$ is called the Bohr magneton $\mu$_B and its value is

${\mu }_B=9.27\times {10}^{-24}{\mathrm{JT}}^{-1}.$