Posted by ronny on Wednesday, May 21, 2008 at 5:51am.
The fraction (1/6) that remains after 70 years satisfies the relation:
1/6 = 2^(-t/T),
where T is the half life and t = 70 years.
Take logs of both sides to solve for T. I'll use logs to base e but it doesn't matter
-1.7918 = -70/T ln 2 = -48.52/T
T = 27.1 years
Related Questions
math - 39mg radioactive with 1/2 life is decay total in 2.5 years. How many mg ...
chemistry - How long will it take for 25% of the C-14 atoms in a sample of C-14 ...
calculus - Carbon-14 is a radioactive substance produced in the Earth's ...
Math - D.E.Q. - The half-life of a radioactive isotope is the amount of time it ...
calculus - The rate at which an amount of a radioactive substance decays is ...
Chem 2 - The half-life for the radioactive decay of U-238 is 4.5 billion years ...
Pre Calculus - Exponential Growth and Decay Find the half-life of a radioactive ...
Science - Radioactive substance decays so that after t years, the amount ...
MATH! - The mass of a radioactive substance follows an exponential decay model, ...
college - a certain radioactive isotope has a half life or 850 years.how many ...
For Further Reading
