A Photon is a discrete packet of electromagnetic radiation . It is the elementary exchange particle for the electromagnetic force. The Energy of a photon depends on its frequency and is given by the equation:
where f is the frequency of the electromagnetic wave and h is Planck's constant and has the numerical value of Js (Joules times second) or eV s (electron volts times second).
- A French, P Taylor.(1978). A Introduction to Quantum Physics. MIT: CRC Press.