- noun the SI unit of measurement of radiation, 1 becquerel being the amount of radioactivity in a substance where one nucleus decays per second.
- The SI unit of activity. It represents one event per second. It is utilized to measure events that happen in an unpredictable manner, such as radioactive disintegrations. This contrasts with hertz, which measures the frequency of phenomena occurring in a periodic cycle, such as electromagnetic waves. Its symbol is Bq.