HSC Together > Year12 > Radiation & Half Lives


Radiation & Half Lives

This section is part of the HSC Physic syllabus Module 8: From the Universe to the Atom.

In this post, we analyse the decay of unstable nuclei. In particular, we will analyse the spontaneous decay of unstable nuclei, and the properties of the alpha, beta and gamma radiation emitted.

Some information about the following decays:

  • Alpha decay is the release of a Helium Atom
  • Beta-decay is the release of an electron
  • Gamma Decay is the release of gamma radiation.

Another interesting term is “half-life”, this is the time taken for an isotope to decay to half its original mass.


Alpha, Beta & Gamma Radiation



Now that we know about radiation we can also understand half-lives. Let’s examine the model of half-life in radioactive decay and make quantitative predictions about the activity or amount of a radioactive sample.