Changes

'''Annihilation''' is the process in which [[matter]] and [[antimatter]] interact converting all their [[Rest Mass|rest mass]] into [[energy]] resulting in a pair of two or more [[Gamma Ray-ray|gamma ray]] [[photon]]s being emitted in opposite directions.

: *'''Annihilation''' occurs when [[particle]]s of [[matter]] and [[antimatter]] interact at extremely close range.: *Follows the principle of [[Mass-Energy Equivalence|mass-energy equivalence]] (E=mc²).*Results in the production of [[Gamma-ray|gamma rays]] or other [[Subatomic Particle|particles]]. However, for a-level physics, you only need to consider the special case of 2 [[Gamma-ray|gamma ray]] [[photon]]s being [[emit]]ted.*During '''annihilation''' the total [[Rest Mass|rest mass]] of, as well as their the [[Kinetic Energy|kinetic energy]] results in , of the [[particle]]s before the event is equal to the production total [[energy]] of the products (two [[Gamma Ray-ray|gamma ray]] [[photon]]sin a-level physics) after the event.: *In '''annihilation''' [[Conservation of Momentum|conservation of momentum]] is conserved due to the [[momentum]] of the two [[Gamma Ray-ray|gamma ray]] [[photon]]s travelling in opposite directions. *[[Annihilation]] can occur in high-energy environments such as the vicinity of black holes and in particle accelerators.

 <math>E_0</math> = Rest Mass Energy of each particle. <math>hf</math> = The [[energy]] of one each[[Gamma Ray-ray|gamma ray]] [[photon]] emitted.