A research assistant made 160 mg of radioactive sodium (Na^24) and found that there was only 20 mg left 45 h later, how much of the original 20 mg would be left in 12 h?
2 Answers
Explanation:
Let rate of decay be
So we can write
or
or
or
or
Similarly after
Just to use the conventional radioactive decay model as a slight alternative method.
After 12hr we have 11.49mg
Explanation:
Let
It's a fairly simple model to solve with ODEs but as it's not really related to the question, we end up with
First we find the value of
Take natural logs of both sides:
So starting with