<P> A B q = n N A ln ⁡ (2) t 1 / 2 (\ displaystyle A_ (Bq) = nN_ (A) (\ frac (\ ln (2)) (t_ (1 / 2)))) </P> <P> For instance, on average each gram of potassium contains 0.000117 gram of K (all other naturally occurring isotopes are stable) that has a t 1 / 2 (\ displaystyle t_ (1 / 2)) of 7016402990552000000 ♠ 1.277 × 10 years = 7016403000000000000 ♠ 4.030 × 10 s, and has an atomic mass of 39.964 g / mol, so the amount of radioactivity associated with a gram of potassium is 30 Bq . </P> <P> The following table shows radiation quantities in SI and non-SI units . </P> <Table> Radiation related quantities view ‧ talk ‧ edit <Tr> <Th> Quantity </Th> <Th> Name </Th> <Th> Symbol </Th> <Th> Unit </Th> <Th> Year </Th> <Th> SI Quantity </Th> </Tr> <Tr> <Td> Activity (A) </Td> <Td> curie </Td> <Td> Ci </Td> <Td> 3.7 × 10 s </Td> <Td> 1953 </Td> <Td> 3.7 × 10 Bq </Td> </Tr> <Tr> <Td> becquerel </Td> <Td> Bq </Td> <Td> s </Td> <Td> </Td> <Td> SI </Td> </Tr> <Tr> <Td> rutherford </Td> <Td> Rd </Td> <Td> 10 s </Td> <Td> 1946 </Td> <Td> 1,000,000 Bq </Td> </Tr> <Tr> <Td> Exposure (X) </Td> <Td> röntgen </Td> <Td> </Td> <Td> esu / 0.001293 g of air </Td> <Td> 1928 </Td> <Td> 2.58 × 10 C / kg </Td> </Tr> <Tr> <Td> Fluence (Φ) </Td> <Td> (reciprocal area) </Td> <Td> </Td> <Td> m </Td> <Td> 1962 </Td> <Td> SI </Td> </Tr> <Tr> <Td> Absorbed dose (D) </Td> <Td> erg </Td> <Td> </Td> <Td> erg ⋅ g </Td> <Td> 1950 </Td> <Td> 1.0 × 10 Gy </Td> </Tr> <Tr> <Td> rad </Td> <Td> rad </Td> <Td> 100 erg ⋅ g </Td> <Td> 1953 </Td> <Td> 0.010 Gy </Td> </Tr> <Tr> <Td> gray </Td> <Td> Gy </Td> <Td> J ⋅ kg </Td> <Td> </Td> <Td> SI </Td> </Tr> <Tr> <Td> Dose equivalent (H) </Td> <Td> röntgen equivalent man </Td> <Td> rem </Td> <Td> 100 erg ⋅ g </Td> <Td> 1971 </Td> <Td> 0.010 Sv </Td> </Tr> <Tr> <Td> sievert </Td> <Td> Sv </Td> <Td> J ⋅ kg × W </Td> <Td> 1977 </Td> <Td> SI </Td> </Tr> </Table>

Potassium is measured in which of the following units