Neptunium-239 has a half-life of 2.35 days.How many days must elapse for a sample of ²³⁹Np to decay to 0.100% of its original quantity?

Question

Quizplus · Accepted Answer

To find the number of days for a sample to decay to 0.100% of its original quantity, we use the half-life formula. The formula to calculate the number of half-lives (n) that have passed is given by: n = (log(final amount/original amount)) / log(0.5). For a decay to 0.100% (which is 0.001 of the original amount), we calculate n as follows: n = log(0.001) / log(0.5) ≈ 9.96578 half-lives. Since each half-life of Neptunium-239 is 2.35 days, the total time is about 9.96578 * 2.35 days ≈ 23.4 days.

Neptunium-239 Has a Half-Life of 2