The speed of an electron (v), in the lowest energy orbit in the bohr model of the hydrogen atom divided by the speed of light in vacuum (c), is given by (where

The speed of an electron (v), in the lowest energy orbit in the Bohr model of the Hydrogen atom divided by the speed of light in vacuum (c), is given by (where m is the mass of the electron, M is the mass of the proton, E is the permittivity of free space, ag is the Bohr radius)