The half-life of radioactive strontium-90 is approximately 27 years. In 1961, radioactive strontium-90 was released into the atmosphere during testing of nuclear weapons, and was absorbed into people's bones. How many years does it take until only 7 percent of the original amount absorbed remains?
time = _________ years
Thank you!
time = _________ years
Thank you!
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fraction remaining, f = 0.5^(t/h) , where h is the half-life
0.07 = 0.5^(t/27)
(t/27)*log 0.5 = log 0.07
t = 27*log 0.07 / log 0.5 = 103.59 ≈ 104 years <-------
0.07 = 0.5^(t/27)
(t/27)*log 0.5 = log 0.07
t = 27*log 0.07 / log 0.5 = 103.59 ≈ 104 years <-------