Radioactivity quantities

Radioactivity refers to the process by which unstable atomic nuclei lose energy by emitting radiation. The key quantities related to radioactivity include: 1. **Activity (A)**: This is a measure of the rate at which a radioactive substance undergoes decay. Activity is typically expressed in becquerels (Bq), where 1 Bq equals one decay event per second. Another unit of measurement is the curie (Ci), where 1 Ci is equivalent to 3.