photon

(noun)

the quantum of light and other electromagnetic energy, regarded as a discrete particle having zero rest mass, no electric charge, and an indefinitely long lifetime

Related Terms

Examples of photon in the following topics:

  • Light

    • Light is composed of photons that make up electromagnetic waves, which are characterized by wavelength, frequency, and amplitude.
    • The behavior of light can be described in terms of the behavior of waves and the behavior of the fundamental unit of light, the photon: a packet of electromagnetic radiation.

  • Processes of the Light-Dependent Reactions

    • When a chlorophyll a molecule within the reaction center of PSII absorbs a photon, the electron in this molecule attains a higher energy level.
    • Therefore, another photon is absorbed by the PSI antenna.

  • Electron Shells and the Bohr Model

    • Energy from a photon of light can bump it up to a higher energy shell, but this situation is unstable and the electron quickly decays back to the ground state.
    • In the process, a photon of light is released.

  • Microscopy

    • Electrons have short wavelengths (shorter than photons) that move best in a vacuum, so living cells cannot be viewed with an electron microscope.