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?

(1/2)xn
(1/n)^2
(1/2)^n
1/(2n)

We know that a half-life is the time taken for the activity of a radioactive sample to be reduced to half.
After one half-life, the activity is 1/2 times the original = (1/2)¹
After two half-lives, the activity is 1/4 times the original = (1/2)²
After three half-lives, the activity is 1/8 times the original = (1/2)³

Therefore, the remaining amount of a sample after n half-lives is (1/2)ⁿ

It d from what i know