A photon is a fundamental particle of light and electromagnetic radiation. It is the basic unit of light and carries energy and momentum.
According to the theory of relativity, a photon has zero rest mass. This means that it does not have mass at rest, but it does have energy and momentum.
The momentum of a photon is determined by its energy and wavelength. The equation for momentum of a photon is p = E/c, where p is momentum, E is energy and c is the speed of light.
A photon travels at the speed of light, which is approximately 299,792,458 meters per second in a vacuum. This speed is constant and does not change regardless of the energy or wavelength of the photon.
The wavelength of a photon is directly proportional to its energy and inversely proportional to its frequency. This means that as the wavelength increases, the energy decreases and vice versa. The wavelength also determines the color of the light, with shorter wavelengths appearing blue and longer wavelengths appearing red.