Question

The half-life of a radioactive kind of iodine is 21 hours. How much will be left after 42 hours,if you start with 19,296 grams of it?In grams

Answer 1

The half-life of a radioactive material is the time that it takes to reduce to half

In this case, the half-life is 21 hs, and since 42hs is twice the half-life, the material will reduce to half after 21 hours and then to half again.

one half of one half is:

`(1)/(2)\cdot(1)/(2)=(1)/(4)`

Then we multiply by the initial amount:

`19,296\cdot(1)/(4)=4824gr`

The amount left after 42 hours is 4824 grams.