Emission

Atoms, molecules, or solids exposed to high energy levels can change to lower levels by emitting radiation; emissions. The four most common types being: alpha particles, beta particles, gamma rays, and x rays.

Light can be produced by matter in an excited state. The atoms and molecules that make up matter typically emit light at various energies. The frequencies of light that an atom can emit are dependent on states of the electrons. When excited, an electron moves to a higher energy level or orbital - the light is emitted once the electron falls back to ground level.