Bohr radius

In the Bohr's model of the hydrogen atom, the Bohr radius is the distance between the electron and the proton.

Formula

a_{0}\ =\ {\frac {h^{2}\varepsilon _{0}}{\pi m_{e}q^{2}}} where h is the Planck constant, ε0 the vacuum permittivity, me the mass of an electron and q the elementary charge. a0=5,29177.10 -11 m