When a particle meets its equivalent anti–particle they both are destroyed and their mass is converted into energy in the form of two gamma ray photons
When an electron and positron collide, their mass is converted into energy in the form of two photons emitted in opposite directions
Emin = hfmin = E
E = hf
When a photon interacts with a nucleus or atom and the energy of the photon is used to create a particle–antiparticle pair
When a photon with enough energy interacts with a nucleus it can produce an electron-positron pair
Emin = hfmin = 2E
Calculate the maximum wavelength of one of the photons produced when a proton and antiproton annihilate each other.
Since the Planck constant is in Joules (J) remember to always convert the rest mass-energy from MeV to J.