What is the term for the process by which unstable nuclei lose energy by emitting radiation?

The process by which unstable nuclei lose energy by emitting radiation is known as radioactive decay. During this process, unstable isotopes transform into more stable forms by releasing energy in the form of radiation. This emission can include alpha particles, beta particles, or gamma rays, depending on the type of decay the nucleus undergoes.

Radioactive decay is a fundamental concept in nuclear physics and is crucial for understanding phenomena such as radiation safety, the behavior of radioactive materials, and the principles behind various medical and industrial applications of radiation. This process is spontaneous and occurs naturally in certain isotopes, which have an inherent instability due to excess energy or mass.

Other terms like nuclear fission refer to the splitting of a nucleus to release energy, while radiation absorption involves the uptake of radiation by materials, and energy transformation is a broader concept that doesn't specifically address the emission of radiation from unstable nuclei. Therefore, radioactive decay is the most accurate term for the described process.