Question

After 432 years a sample of an unknown radioactive isotope has decayed 5 points3 times. What is the unknown isotope's half life? Be sure you answer has 2significant figures. Show/Attach ALL YOUR WORK for full credit.1 Add file

Answer 1

`140\text{ years}`

Step-by-step explanation:

Here, we want to get the half life of the given radioactive isotope

From the question, we are told that it has decayed three times in 432 years

Mathematically, if we divided 432 by 3, we will get 144

So, what this mean is that, it had it first decay after 144 years, then it took another 144 before the last 144

What we have to do finally here is to convert 144 to 2 significant figures

We have this as 140 years