https://doi.org/10.1351/goldbook.D01538
Proportionality constant relating the activity of a @[email protected] substance, A, to the number of decaying particles B, \(N_{\text{B}}\), \(A=\lambda \ N_{\text{B}}\). @[email protected] of a @[email protected] within a time interval divided by that time interval. Synonymous with @[email protected]