Radioactive Decay Calculation
The radioactive half-life for a given radioisotope is a measure of the tendency of the nucleus to "decay" or "disintegrate" and as such is based purely upon that probability. Alternatively, this information can be expressed in terms of the decay constant λ. The number of atoms, the mass of the substance, and the level of activity all follow the same exponential decay form. The calculation below is stated in terms of the amount of the substance remaining, but can be applied to intensity of radiation or any other property proportional to it.