Decay constant

Definition

The decay constant, denoted by $\lambda$, is a probability rate at which a particular radioactive isotope decays per unit time. It is a fundamental property of the radioactive substance.

5 Must Know Facts For Your Next Test

1. The decay constant $\lambda$ is related to the half-life $T_{1/2}$ by the formula $\lambda = \frac{\ln(2)}{T_{1/2}}$.
2. It has units of inverse time (e.g., s$^{-1}$, min$^{-1}$).
3. A larger decay constant indicates a faster decay rate of the radioactive material.
4. Activity, measured in becquerels (Bq), is given by $A = \lambda N$, where $N$ is the number of undecayed nuclei.
5. The decay constant is independent of external physical conditions such as temperature and pressure.

Review Questions

Related terms

Half-Life: The time required for half of the radioactive nuclei in a sample to undergo radioactive decay.

Activity:

The number of disintegrations per second occurring in a sample, usually measured in becquerels (Bq).

$N_0$:

$N_0$ represents the initial quantity of undecayed nuclei present at time zero.