4. Alpha, beta, gamma
The three main types of nuclear radiation are Alpha, Beta, & Gamma.
Nuclear radiation refers to the particles and photons emitted during a reaction involving the nucleus of an atom.
The particles released by a nuclear reaction are powerful enough to remove electrons from atoms and molecules and ionize 'em.
Gamma rays have the shortest wavelengths of all electromagnetic radiation and having a greatest penetration power. Gamma rays can pass completely into the human body. As they pass, they can ionize causing damage in tissues and DNA.