What type of radiation is known to have no mass and is the fastest moving?

Gamma rays are a form of electromagnetic radiation and are characterized by having no mass and no charge. They are produced during nuclear reactions and decay processes, making them highly penetrating compared to other forms of radiation. Their lack of mass allows them to travel at the speed of light, which is the fastest speed possible in the universe.

This property enables gamma rays to traverse various materials more effectively than alpha and beta particles, which do have mass and therefore interact more readily with matter, losing energy and speed in the process. This makes gamma radiation particularly significant in both radiation safety and health physics, as it can pose serious barriers to shielding and protection measures. The high penetration power of gamma rays often necessitates the use of dense materials like lead or concrete for effective shielding, contrasting with the more contained nature of alpha and beta radiation.