How much of a sample remains after five half-lives have occurred? o 1/5 of the original sample 01/25 of the original sample o 1/32 of the original sample o 1/64 of the original sample

Every half-life, we end up with half of the material we started with. At the beginning, we have all of the material, which we can represent with the number 1. After one half-life, we have 1 • 1/2 = 1/2 left.

After two: 1/2 • 1/2 = 1/4

Three: 1/4 • 1/2 = 1/8

Four: 1/8 • 1/2 = 1/16

And five: 1/16 • 1/2 = 1/32.

In general, after n half-lives, we’ll have 1/(2^n) of the material left over.