Question

The half-life of ^60Co (Cobalt-60) is 5.27 years. How long does it take for 50 grams of ^60Co to decay to 20 grams?

Answer 1

\[^{60}Co\]

Answer 2

\[20=50\times (\frac{1}{2})^{\frac{t}{5.27}}\] solve for t

Answer 3

\[\frac{2}{5}=.4=(\frac{1}{2})^{\frac{t}{5.27}}\]
\[\frac{t}{5.27}=\frac{\ln(.4)}{\ln(.5)}\]
\[t=\frac{5.27\ln(.4)}{\ln(.5)}\] then a calculator

Answer 4

t = 1.3219, thanks so much! :)