If the radioactivity of a material is not known, what can be said about the determination of its half-life?

The determination of the half-life of a radioactive material relies fundamentally on understanding its radioactivity and decay characteristics. If the radioactivity of the material is not known, it means that there is insufficient information regarding how quickly the material is decaying, which is essential for calculating its half-life.

The half-life is defined as the time required for half of the radioactive nuclei in a sample to decay. Without knowing the initial amount of radioactive material or how much of it remains after a given time, one cannot establish a precise relationship that leads to the determination of the half-life. Therefore, if radioactivity is not known, it is indeed correct to say that the half-life cannot be determined.

In contexts where estimations or calculations are possible, they depend on data about the decay rates or remaining quantities of the substance at different times, which are not available if the radioactivity is completely unknown.