What is the activity of the same radium-226 sample re-measured in 2025?

To determine the activity of a radium-226 sample in 2025, it is important to consider the concept of half-life and how the activity of a radioactive isotope decreases over time. Radium-226 has a half-life of approximately 1,600 years. This means that after every 1,600 years, the amount of radium-226 present will reduce to half of its initial quantity, and consequently, its radioactivity will also decrease to half.

Assuming the original activity of the radium-226 sample was 3.74 x 10^6 disintegrations per second, we can calculate its activity in 2025, which is about a century from a common starting point of around 1925, allowing us to find out how much decay has happened.

To find the remaining activity after about 100 years, we can use the decay formula, which incorporates the half-life of the substance. Since 100 years is less than one half-life, this means the activity will not halve completely, but will reflect a reduced value of the initial activity.

The final activity of the radium-226 sample in 2025 would approximately be calculated to be around 3.58 x 10^6 disintegrations