Energy b . Antimatter a . Every particle has an antiparticle which is identical except the charge is opposite. When two antiparticles collide, they annihilate each other and emit two or more photons. The excess mass energy goes into kinetic energy of the fragments 4 .
Beta decay can also occur to a nuclear neutron but with a different half-life.
Process through which an excited nucleus returns to its ground state. This process does not change the Z or N number but is a general example of radioactive decay. Nuclear Reactions A . Q-value 1 . Nuclear binding energies - Fission and Fusion 1 .