decay constant

https://doi.org/10.1351/goldbook.D01538
Proportionality constant relating the activity of a @R05077@ substance, A, to the number of decaying particles B, \(N_{\text{B}}\),\(A=\lambda \ N_{\text{B}}\). @P04855@ of a @N04227@ within a time interval divided by that time interval. Synonymous with @D01786@.
Source:
Green Book, 2nd ed., p. 22 [Terms] [Book]