SOLUTION: Find the half-life of a radioactive substance that decays by 2% in 9 years.

Question 822989: Find the half-life of a radioactive substance that decays by 2% in 9 years.
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Find the half-life of a radioactive substance that decays by 2% in 9 years.
:
Using the radioactive decay formula; A = Ao*2^(-t/h), where:
A = amt remaining after t time
Ao = initital amt (t=0)
t = time of decay
h = half-life of substance
:
Let initial amt = 1, then resulting amt after 9 yrs = .98 (2% less)
1*2^(-9/h) = .98
using nat logs
ln(2) = ln(.98)
=
= -.029
h =
h = 309 yrs is the half life
:
:
Check this on your calc; enter 1*2^(-9/309); results .98 or 98% remains
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