WUSTL Radiation Safety Training 2025 – 400 Free Practice Questions to Pass the Exam

Isomeric transition refers to a type of radioactive decay that involves the transition between different energy states of a nuclide without the emission of particles like alpha or beta particles. During this process, an excited nucleus returns to a lower energy state, often by releasing energy in the form of gamma radiation. This occurs without any change in the number of protons or neutrons within the nucleus, which is a key characteristic distinguishing it from other decay processes.

In contrast, alpha decay involves the emission of an alpha particle (consisting of 2 protons and 2 neutrons), while beta decay involves the conversion of a neutron to a proton or vice versa with the emission of beta particles (electrons or positrons). The mention of "subjective decay" is not an established term in the field of radioactive decay, making it irrelevant in this context. Therefore, isomeric transition is the only type listed that occurs without particle emission, making it the correct choice.