Rate of decay

Definition

Rate of decay measures how quickly a radioactive substance undergoes radioactive decay. It is often quantified by the activity, which is the number of disintegrations per unit time.

5 Must Know Facts For Your Next Test

1. The rate of decay is directly proportional to the number of undecayed nuclei present.
2. It can be expressed mathematically as $A = \lambda N$, where $A$ is the activity, $\lambda$ is the decay constant, and $N$ is the number of undecayed nuclei.
3. The rate of decay decreases over time as the substance decays.
4. It is commonly measured in becquerels (Bq) or curies (Ci).
5. Understanding the rate of decay helps in calculating the half-life and predicting how long a radioactive material will remain hazardous.

Review Questions

Related terms

Half-Life: The time required for half of a sample of a radioactive substance to decay.

Decay Constant:

$\lambda$, a probability per unit time that a nucleus will decay.

Activity:

The number of disintegrations per unit time in a radioactive sample, usually measured in becquerels (Bq).