The original amount of a radioactive sample should be multiplied by which expression to calculate the amount of the sample that remains after n half-lives have passed?

Each half-life leaves one-half of the sample that was present before it. After n half-lives, the remaining fraction is therefore (1/2) multiplied by itself n times, or (1/2)^n. The correct choice is “1 half to the nth power”; 1/(2n) does not represent repeated halving.

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