A thallium source with a half-life of $3.7$ years was certified at $10 \mathrm { kBq }$ ten years ago. What is its activity now?

Question

Quizplus · Accepted Answer

The activity of a radioactive source decreases over time according to the formula $A = A_0 \times (1/2)^{t/T}$, where $A$ is the final activity, $A_0$ is the initial activity, $t$ is the time elapsed, and $T$ is the half-life of the substance. Here, $A_0 = 10 \, \mathrm{kBq}$, $t = 10$ years, and $T = 3.7$ years. Plugging these values into the formula gives $A = 10 \times (1/2)^{10/3.7} \approx 1.5 \, \mathrm{kBq}$.

A Thallium Source with a Half-Life Of 3.73.73.7 Years Was Certified At

A Thallium Source with a Half-Life Of $3.7$ Years Was Certified At