Half-life

The quantity half-life (t_½) is the period of time after which the activity is reduced to half the original value. De corresponding unit is second (s).

The quantity decay constant (commonly denoted by the Greek letter λ) is the fraction of the activity that decays per unit of time (in s). The relation between half-life and decay constant is:

λ = ln(2) / t_½

Related concepts

• activity
• atom
• decay constant
• electromagnetic radiation
• electron
• molecule
• neutrino
• neutron
• nuclear decay
• positron
• proton
• X-radiation