Activity (Basics)

Activity represents the total number of disintegrations
(decays) of parent nuclei per unit time.
􀀁 The SI unit of activity is the becquerel (1 Bq = 1 s-1).
Both the becquerel and the hertz correspond to s-1, however, hertz
expresses frequency of periodic motion, while becquerel expresses
activity.
􀀁 The older unit of activity is the curie ,
originally defined as the activity of 1 g of radium-226.
Currently, the activity of 1 g of radium-226 is 0.988 Ci.
(1 Ci = 3.7 􀀂 1010 s􀀁1)