Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
A photon is a fundamental particle of light that behaves both as a wave and a particle. It is the quantum of electromagnetic energy, including visible light and other forms of radiation.
Related terms
Electromagnetic Spectrum: The range of all types of electromagnetic radiation from radio waves to gamma rays.
The layer at the back of the eyeball containing cells that are sensitive to light and trigger nerve impulses that pass via the optic nerve to the brain where a visual image is formed.
Visual Perception: The ability to interpret the surrounding environment by processing information contained in visible light reaching the eye