A photon is a fundamental particle of light and electromagnetic radiation. It is a type of elementary particle that carries electromagnetic force and has zero mass, zero electric charge, and a spin of 1. It is considered to be a quantum of energy, and its energy is directly proportional to its frequency. Photons are responsible for all electromagnetic interactions, including light, radio waves, X-rays, and gamma rays. They are also involved in many other physical phenomena, such as the photoelectric effect, which is the basis of solar cells and other technologies.