Answer;
2 half lives
Explanation;
-Half life is the time taken by a radioactive isotope to decay to half of the original amount.
-For example; if the original mass is 100% the time it takes to decay to 50% is the half life.
-Therefore, in our case; for the element to decay from 1 whole to a half of the element, is one half life, then decaying from a half to one-fourth of the element will be another half life, which means there are two half lives for an element to decay to one-fourth of the element.
