What is beta decay?

Beta decay is a specific type of radioactive decay characterized by the emission of beta particles from an unstable atomic nucleus. In this process, a neutron in the nucleus is transformed into a proton, which leads to the release of a beta particle, either in the form of an electron or a positron, depending on the type of beta decay occurring. This transformation is a way for the nucleus to move towards a more stable configuration, resulting in a change in the atomic number of the element and thus transforming it into a different chemical element or isotope.

The mechanism behind beta decay is crucial in understanding various phenomena in nuclear physics and is relevant for fields such as radiopharmaceuticals and radiation safety. The other options provided describe different concepts: the first option relates to alpha particles, which are not involved in beta decay; nuclear fission describes the splitting of a heavy nucleus into smaller components, and radiation therapy refers to the medical use of ionizing radiation to treat cancerous cells, none of which accurately describe beta decay.