SOLUTION: The half-life of a radioactive substance is the time it takes for half of the material to decay. Phosphorus-32 is used to study a plant's use of fertilizer. It has a half-life of 1

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: The half-life of a radioactive substance is the time it takes for half of the material to decay. Phosphorus-32 is used to study a plant's use of fertilizer. It has a half-life of 1      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 851389: The half-life of a radioactive substance is the time it takes for half of the material to decay. Phosphorus-32 is used to study a plant's use of fertilizer. It has a half-life of 14.3 days. How many milligrams of phosphorus-32 remain after 92 days from a 100 milligram sample? Express the answer to the nearest whole milligram.
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
The half-life of a radioactive substance is the time it takes for half of the material to decay.
Phosphorus-32 is used to study a plant's use of fertilizer.
It has a half-life of 14.3 days.
How many milligrams of phosphorus-32 remain after 92 days from a 100 milligram sample?
Express the answer to the nearest whole milligram.
:
Use the radioactive decay formula: A = Ao*2(-t/h); where:
A = remaining amt after t time
Ao = Initial amt (t=0)
t = time of decay
h = half-life of substance
:
A = 100*2^(-92/14.3)
Find 2^(-92/14.3) with your calc
A = 100 * .01157
A = 1.157 mg after 92 days, rounds to 1 mg