SOLUTION: Consider that the half-life of Polonium-210 is 140 days. 10. What approximate daily percentage of decay does Polonium-210 demonstrate? % (Round to two decimals.) (Hint: u

Algebra ->  Customizable Word Problem Solvers  -> Misc -> SOLUTION: Consider that the half-life of Polonium-210 is 140 days. 10. What approximate daily percentage of decay does Polonium-210 demonstrate? % (Round to two decimals.) (Hint: u      Log On

Ad: Over 600 Algebra Word Problems at edhelper.com


    

Question 941762: Consider that the half-life of Polonium-210 is 140 days.

10. What approximate daily percentage of decay does Polonium-210 demonstrate?
% (Round to two decimals.)
(Hint: use the Rule of 70 backwards by dividing by the half-life period instead of the rate.)

11. What percentage of the original amount of Polonium-210 would be left after 525 days of decay?
% (Round to two decimals.)
Answer by josgarithmetic(39613) About Me  (Show Source):
You can put this solution on YOUR website!
What is the rule of 70?
Use the half-life to find the decay constant in y=Ie%5E%28-kt%29.
You know that %281%2F2%29=1%2Ae%5E%28-k%2A140%29,
1%2F2=e%5E%28-k%2A140%29
ln%281%2F2%29=-k%2A140+
ln%282%29=k%2A140
k=%281%2F140%29ln%282%29

k=0.00495

y=Ie%5E%28-0.00495t%29-----reminder, this is exponential. No average makes sense here, unless for some limited time period.