Question

Half life of Uranium is 4.47x10^9 years.In how much time only 10g will be left out of 40g? (Medal for the answer).

Answer 1

Each time a half-life of a radioactive substance passes, about half of the substance decays into a different element. Using this information, you should be able to figure it out.

Answer 2

if you cut 40g in half, you get ....?

if you cut that amout in half again, you get ....?

So how many half-lives have passed, and how many years is that?