Exponential radioactive decay
A fixed decay probability per time gives a population timescale.
Key knowledge
For a single nuclide with constant decay constant λ > 0, expected undecayed population is N(t) = N₀e^(−λt), activity is λN and half-life is ln 2/λ.
Values and equations
N(t) = N₀e^(−λt); activity = λN(t); t_½ = ln 2/λ
- N, N₀
- Expected undecayed population and initial population
- λ
- Decay constant s⁻¹
- t, t_½
- Elapsed time and half-life s
- activity
- Expected decay rate Bq
Conditions and scope
- No production, daughter feeding, transport or competing changes to the stated population/model.
- Individual decay times are stochastic; dating requires additional isotope and closed-system assumptions.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Equations 10.10, 10.17–10.18: exponential population, half-life and activity.
2026-10-10 · Single constant-rate decay population model only; no geochronological date or exact individual lifetime claim.
Entry details
Permanent link to this entry ↗- Record identity
- physics-radioactive-decay
- Revision
- university-reference.1
- Structured reference record
- University reference · University core expansion