Becquerel a gram of potassium is 30 Bq. The following table shows radiation quantities in SI and non-SI units. Becquerel The becquerel (; symbol: Bq) is the SI derived unit of radioactivity. One becquerel is defined as the activity of a quantity of radioactive material in which one nucleus decays per second. The becquerel is therefore equivalent to an inverse second, s. The becquerel is named after Henri Becquerel, who shared a Nobel Prize in Physics with Pierre and Marie Curie in 1903 for their work in discovering radioactivity. As with every International System of Units (SI) unit named for a
2019 redefinition of SI base units seven base units whose definitions are unconstrained by that of any other unit and another twenty-two named units derived from these base units. The metre was redefined in terms of a wavelength of krypton-86 radiation, making it derivable from universal natural phenomena, but the kilogram remained defined in terms of a physical prototype, leaving it the only artefact upon which the SI unit definitions depend. Although designed for long-term stability, the masses of the kilogram prototype and its secondary copies have shown small variations over time relative to each other, and they are not thought to be adequate for the