Speed of light in vacuum
m/s
The speed of light in vacuum is an exact defining constant of the SI: 299792458 m/s, and its fixed value defines the meter. In chemistry it is used in spectroscopy through E = hc/λ, converting between a photon's wavelength and its energy, and it underlies all electromagnetic radiation calculations.
Used in
- Spectroscopy
- Photon energy calculations
Source: SI Brochure 9th ed. — exact defining constant