The radioactive isotope of lead, Pb-209, decays at a rate
Chapter 3, Problem 3.1.5(choose chapter or problem)
The radioactive isotope of lead, Pb-209, decays at a rate proportional to the amount present at time t and has a halflife of 3.3 hours. If 1 gram of this isotope is present initially, how long will it take for 90% of the lead to decay?
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