Plutonium has a half-life of 23,105 years. What percentage of a sample of Plutonium has decayed after 10,000 years?
Use the half-life formula:
Substitute t=10,000 years and thalf-life \(=23,105t\):
\(N \sim 0.74N0\)
This means that 74% of the sample remained. Hence, 26% of the sample of Plutonium decayed.