A beta particle is a type of subatomic particle that is emitted during the radioactive decay of certain unstable atomic nuclei. It can be either an electron (beta-minus) or a positron (beta-plus). Beta particles are much lighter than alpha particles and carry a single negative or positive charge, respectively. They are a form of ionizing radiation and can penetrate materials more effectively than alpha particles. When a nucleus undergoes beta decay, it transforms into a different element or isotope. This process helps stabilize the nucleus by reducing the number of protons or neutrons. The study of beta particles is important in fields like nuclear physics and medical imaging, particularly in the use of radiotracers for diagnostic purposes.