Show that, in $h=c=1$ units, the Compton wavelength of an electron is $m^{-1}$, the Bohr radius of the hydrogen atom is $(\alpha m)^{-1}$, and the velocity of an electron in its lowest Bohr orbit is simply $\alpha ; m$ is the mass of the electron or, more precisely, the reduced mass $m_{e} m_{p} /\left(m_{e}+m_{p}\right)$.