Here, formula_12 is the permeability of free space, formula_13 is the speed of light, formula_14 is the electric charge of electron, formula_15 is the Bohr's radius, and formula_16 is the frequency of revolution of the electron in a hydrogen atom formula_17. When these constant values are substituted to the theoretical Planck constant, the theoretical Planck constant value is exactly equal to the experimental value.