Answer :
To calculate the time taken for an 80 g sample of Po-212 to decay until only 10 g is left, you need to know the half-life of Po-212 and apply the exponential decay formula, which shows it would take 3 half-lives to reduce to 10 g.
The question pertains to the concept of half-life, which is the time required for half the atoms in a sample to decay. To determine how long it took for an 80 g sample of Po-212 to decay to 10 g, one must know Po-212's half-life. Assuming that the half-life of Po-212 is already known, let's say X hours, we apply the exponential decay formula: final amount = initial amount x (1/2)^(time elapsed/half-life). Given that the decay process is sequential, after the first half-life, 40 g would remain, after the second, 20 g, and after the third, 10 g. Therefore, it takes three half-lives for 80 g to decay to 10 g. If one half-life of Po-212 is X hours, it would take 3X hours for this process to occur.
