Question

Question #0ff3e

Answer 1

`"2 days"`

Explanation:

A radioactive isotope's nuclear half-life tells you how much time must pass in order for half of the atoms present in a sample to undergo radioactive decay.

In your case, you start with `"10 g"` of a radioactive substance. Two days after first interacting with the sample, you find that its mass decreased to `"5 g"`.

This is, of course, equivalent to saying that `"5 g"` of the substance decayed. Since it took `2` days for half of the sample to undergo radioactive decay, you can say that this radioactive isotope has a half-life of `2` days.