Definitions for

**"Decay constant"**the rate of radioactive decay of a nuclide, expressed by (chance of decay/time).

For an atom that undergoes radioactive decay, the decay constant is the proportionality factor between the time rate of decay and the total number of atoms present; it is the inverse of the mean lifetime of an atom. A to F | G to L | M to R | S to Z

the fraction of a number of atoms of a radioactive nuclide that disintegrates in a unit of time. The decay constant is inversely proportional to the radioactive half-life.

An estimate of the decline in product sales if advertising was discontinued.