Radioactivity decay

Half-life (t½)

The time it takes for one half of the radioactive atoms in a sample to decay.

Decay time (Δt)

The time taken for a sample to decay from an initial amount (No) to a final amount (Nf).

Decay constant (λ)

A positive constant that represents the rate of decay, with units of s⁻¹.

Relationship of decay time and half-lives

Δt = n × t½, where Δt is the decay time, n is the number of half-lives, and t½ is the half-life.

Final amount of radioactive atoms (Nf)

The amount of radioactive atoms remaining after a certain period of decay.

Proportional relationship to decay

The rate of decay (activity A) is proportional to the number of parent nuclei (N) present.

Logarithmic relationship of half-life

t1/2 = 0.693 / λ, derived from N = ½ N0 and logarithmic properties of exponential decay.

Number of half-lives (n)

The count of half-life intervals that elapse during a particular decay time.

What is half-life (t½)?

The time it takes for one half of the radioactive atoms in a sample to decay.

How is decay time (Δt) calculated?

Decay time is the time taken for a sample to decay from an initial amount (No) to a final amount (Nf).

What does decay constant (λ) represent?

A positive constant that represents the rate of decay, measured in s⁻¹.

What is the formula relating decay time and half-lives?

Δt = n × t½, where Δt is decay time, n is the number of half-lives, and t½ is the half-life.

What does Nf represent?

Nf is the amount of radioactive atoms remaining after a certain period of decay.

How is the rate of decay related to the number of parent nuclei (N)?

The rate of decay (activity A) is proportional to the number of parent nuclei (N) present.

What is the relationship of half-life to the decay constant?

The half-life is calculated using the formula t1/2 = 0.693 / λ.

What is meant by the number of half-lives (n)?

The count of half-life intervals that have elapsed during a specific decay time.

How does one determine the remaining radioactive material after several half-lives?

By applying the formula Nf = No × (1/2)ⁿ, where n is the number of half-lives completed.

What is radioactive decay?

Radioactive decay is the process by which an unstable atomic nucleus loses energy by emitting radiation.