It's the birthday of Antoine Becquerel, who was born in 1788 in Châtillon-Coligny, France.
After fighting for France in the Peninsular War, Becquerel became a scientist whose research interests were diverse.
He studied the electrical properties of materials, invented the differential galvanometer and discovered a photoelectric effect.
He was also interested in biophysics and meteorology.
Becquerel's son, Edmond Becquerel, and his grandson, Henri Becquerel, were also physicists.
The becquerel (defined as the activity of a quantity of radioactive material in which one nucleus decays per second) unit is named after Henri Becquerel, a Nobel laureate and the discoverer of radioactivity.