The Becquerel is a unit used to measure a radioactivity. One Becquerel is that quantity of a radioactive material that will have 1 transformations in one second.
1 Bq = 1 s-1
As a result of having one Becquerel being equal to one transformation per second, there are 3.7x1010 Bq in one curie.
A unit of radioactivity equal to 1000 atomic disintegrations per second or 27.027 nanocuries (nCi).
See also: Becquerel, Antoine-Henri.