Work out activity (becquerel) instantly with clear inputs, formula shown and shareable results.
Activity is the decay rate, A = lambda.N, so it depends on both how many atoms are present and how unstable they are. 1e18 atoms with a one-day half-life give 8.02e12 Bq, or 217 curies. Because activity is proportional to N, it decays with exactly the same half-life as the sample itself.
Activity
A = lambda N = (ln2 / t(half)) x N
Unit relation
1 Ci = 3.7e10 Bq
It gives higher activity for the same number of atoms, but it also decays away quickly. Hazard depends on activity, radiation type and biological behaviour together.
Because it is one decay per second. A banana registers about 15 Bq, which is why kBq and MBq are used in practice.