Changes

A Photon is a discrete packet of electromagnetic radiation <ref>A French, P Taylor.(1978). A Introduction to Quantum Physics. MIT: CRC Press.</ref>. 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:

A Photon is a discrete packet of electromagnetic radiation.<ref>A French, P Taylor.(1978). A Introduction to Quantum Physics. MIT: CRC Press.</ref> 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:

<math>E = hf</math>

<math>E = hf</math>

where ''f'' is the frequency of the electromagnetic wave and ''h'' is Planck's constant and has the numerical value of <math>6.626\times10^{-34}</math>Js ([[Joule|Joules]] times second) or <math>4.135\times10^{-15}</math>eV s (electron volts times second).   

where ''f'' is the frequency of the electromagnetic wave and ''h'' is Planck's constant and has the numerical value of <math>6.626\times10^{-34}</math>Js ([[Joule]]s times second) or <math>4.135\times10^{-15}</math>eV s (electron volts times second).