The material used in certain nuclear bombs is ²³⁹Pu, which has a half-life of about 20,000 years. How long must we wait for a buried stockpile of this substance to decay to 4.0% of its original ²³⁹Pu mass?

Question

Quizplus · Accepted Answer

The decay of a substance to a certain percentage of its original mass can be calculated using the formula for exponential decay: N(t) = N0 * (1/2)^(t/T), where N(t) is the remaining mass, N0 is the initial mass, t is the time, and T is the half-life. Solving for t when N(t)/N0 = 0.04 and T = 20,000 years gives approximately 93,000 years.

The Material Used in Certain Nuclear Bombs Is 239Pu, Which

The Material Used in Certain Nuclear Bombs Is ²³⁹Pu, Which