What is the activity of a radium-226 sample measured in 1925?

The activity of a radioactive sample is indicative of the number of disintegrations occurring per second, which is directly related to the amount of the radioactive isotope present and its half-life. For radium-226, the half-life is approximately 1,600 years, meaning that it decays relatively slowly compared to many other isotopes.

In 1925, radium-226 would have retained a significant portion of its original activity, as it's not far removed from its date of discovery in 1898. The activity of radium-226 is given by the equation:

Activity (A) = λN

where λ is the decay constant and N is the number of radioactive atoms present. Using the known properties of radium-226, the calculated activity aligns with the value of 3.74 × 10^6 disintegrations per second.

This value comes from calculations based on its decay constant derived from the isotope's half-life and current physical constants at that time. Since 3.74 × 10^6 disintegrations per second is a characteristic number for radium-226 based on historical data, it confirms the answer is accurate for the activity measured in 1925.

The other values provided do not correspond to