Light generally refers to electromagnetic radiation of any wavelength. Visible light constitutes wavelengths of 400 to 700 nm, with frequencies of 750 to 420 THz. The study of optics and of photonics is the study of light. There are three core ways light can be represented:
- As a ray, which is used in the study of geometric optics.
- As a wave, which is used in wave optics.
- And as a particle (a photon), which is used in quantum optics.