Decay Constant

Key Stage 5

Meaning

The decay constant is the probability of an individual nucleus decaying per second.

About Decay Constant

• The decay constant is denoted by the symbol 𝜆.
• The decay constant provides a measure of the rate at which a radioactive substance undergoes decay.
• Higher decay constant indicates a more rapid decay process.
• The decay constant is used in the calculation of the activity of a radioactive sample.

Formula

The decay constant is related to the half-life of a radioactive substance by the formula:

• \(𝜆=\frac{ln(2)}{t_{1/2}}\)

Where:

𝜆 is the decay constant

t_1/2 is the half-life of a given isotope

Examples

• The decay constant of Carbon-14 is used in radiocarbon dating.
• Radon-222 has a higher decay constant than Uranium-238, indicating it decays more rapidly.