decay rate

Main Entry: decay constant
Function: noun
: the constant ratio of the number of radioactive atoms disintegrating in any specified short unit interval of time to the totalnumber of atoms of the same kind still intact at the beginning of that interval called also disintegration constant

decay constant n.

Symbol λ The constant ratio for the number of atoms of a radionuclide that decay in a given period of time compared with the total number of atoms of the same kind present at the beginning of that period. Also called disintegration constant, radioactive constant.