Goes over four different worked examples for calculating activity and half-life from radioactive decay. Activity is defined as the number of decays per second. It is abbreviated with the symbol A and has the metric unit the Becquerel (Bq). One Becquerel is equal to one decay per second. Social Media for Step by Step Science: Teacher Pay Teachers Store: Instagram: Website: Blog: Link Tree: This video can be shared at Please support my channel by doing all of the following: (1) Subscribe, get all my physics, chemistry and math videos. (2) Give me a thumbs up for this video. (3) Leave me a nice positive comment. (4) Sharing is Caring, sharing this video with all of your friends.