Nuclear Physics covers the structure of the atom and radioactivity.
An atom has a central nucleus (protons and neutrons) surrounded by electrons. Unstable nuclei emit alpha, beta or gamma radiation. Gamma is the most penetrating. The half-life is the time for half a sample to decay.
Remember
- Nucleus = protons + neutrons; electrons orbit it.
- Three radiations: alpha, beta, gamma (gamma most penetrating).