Question

If there are 360 grams of radioactive material with a half-life of 8 hours, how much of the radioactive material will be left after 32 hours? Is the radioactive decay modeled by a linear function or an exponential function?

Answer 1

22.5 grams; exponential

Explanation:

Did it on usa test prep and got it right

Answer 2

There will be 22.5 grams left after 32 hours.

Explanation:

A half-life is how long it takes for half of the amount to go away. In this case, we see that we have two half-life periods worth, which you can determine by dividing the total time by the half-life time.

32hrs/8hrs = 4 half lives.

Now we can raise 1/2 to the power of how many half lives we have (2). Then we multiply that by the amount in the sample.

(1/2)^4 * 360

1/16 * 360

22.5 grams

And this is an exponential function.