Question

Three radioactive elements have half-life of A,B,C. A>B>C. Assume that there are 1 lakh atoms in each element. For which element, it will take the least time to decay 50 thousands atoms?

Answer 1

The time in which half of the original number of nuclei decay is defined as the half-life, t1/2. Half of the remaining nuclei decay in the next half-life. Further, half of that amount decays in the following half-life.

Radioactive element C will take the least time to decay 50 thousands atoms, because element C has the smallest half-life.