Answer to Question #165945 in Physics for Sam

Question

Which type of radiation is the most penetrating? Which is the most ionising?

Answer 1

There are three types of radiation: alpha-particles, beta-particles and gamma radiation.

a) Gamma radiation (or gamma rays) has the most penetrating power of all three types of radiation because gamma rays have no charge and, hence, do not interact with matter as strongly as do charged particles.

b) Alpha-radiation (or alpha-particles) has the most ionising power of all three types of radiation because of double positive charge of the alpha-particles, large mass (compare to beta-particles) and relative slow speed (compare to beta-particles and gamma radiation). As a result, alpha-particles can cause multiple ionisations within a very small distance.