n represents an integer (particularly the Bohr quantum numbers).
The velocity of light is c = 3 × 10¹⁰ cm. per second = 9·9 × 10⁸ feet per second.
The wave-length of yellow sodium light is 0·589 μ = 589 μμ = 2·32 × 10⁻⁵ inches.
The frequency of yellow sodium light is 526 × 10¹² vibrations per second.
The number of molecules per cm.³ at 0° C. and atmospheric pressure is about 27 × 10¹⁸.
The number of hydrogen atoms in 1 g. is about 6·10²³.
The mass of a hydrogen atom is 1·65 × 10⁻²⁴ g.
The elementary quantum of electricity is 4·77 × 10⁻¹⁰ “electrostatic units.”
The negative electric charge of an electron is 1 elementary quantum (1 negative charge).
The positive electric charge of a hydrogen nucleus is 1 elementary quantum (1 positive charge).