Curie << KYUR ee >> is a unit of radioactivity. Its symbol is Ci. It is named in honor of the French physicist Pierre Curie, husband of Marie Curie. The couple both studied radioactivity. One curie equals 37 billion nuclear decays per second. These decays involve the emission of particles by certain atomic nuclei (cores). The radioactivity of 1 gram of radium equals about 1 curie. In 1975, the curie was replaced with another unit of radioactivity called the becquerel (Bq). One becquerel equals one decay per second. One curie equals 3.7×1010 becquerels.
