|Physical quantity (s)||activity|
|In SI units|
|Named after||Marie and Pierre Curie|
|Derived from||Activity of radium -226|
|See also: Becquerel|
Curie is the obsolete unit of activity of a radioactive substance with the symbol Ci; it was used temporarily until 1985, when it was replaced by the SI unit Becquerel . Today it is only used in materials testing. 1 curie was originally defined as the activity of 1 g of radium -226, and later set to the approximately same value of 3.7 · 10 10 Becquerel (= 37 GBq).