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Formula Radioactive Decay Half-life    Decay constant

Formula: Radioactive Decay
Radioactive decay law - Graph


Half-life is the period of time after which the initial amount of atomic nuclei has decayed to half.

Decay constant

Decay constant specifies the probability of decay per unit of time. In other words: The decay constant determines how fast a nuclide (radioactive substance) decays. Different nuclide decay at different rates.

The reciprocal of the decay constant is the lifetime: \( \tau = \frac{1}{\lambda} \).