Question

The half-life of a radioactive isotope is the time it takes for a quantity of the isotope to be reduced to half its initial mass. Starting with 195 grams of a radioactive isotope, how much will be left after 6 half-lives?

Use the calculator provided and round your answer to the nearest gram.

Answer 1

Half of the starting amount remains after 1 half-life. So after 6 half-lives, the starting amount is halved 6 times, meaning that a 195 g sample would decay down to

(195 g)/2^6 = 195/64 g ≈ 3 g