Americium-241 is an artificially produced radioactive element that emits 
-particles. A sample of americium-241 of mass 
is found to have an activity of 
.
Determine, for this sample of americium-241,
the number of nuclei,
the decay constant,
the half-life, in years.
Another radioactive element has a half-life of approximately 4 hours. Suggest why measurement of the mass and activity of a sample of this element is not appropriate for the determination of its half-life.
.
.
