Question

The half-life of P-32 is 14 days. How long after a sample is delivered can a laboratory wait to use a sample in an experiment if they need at least 10 percent of the original radioactivity? a) 4.67 days b) 6.91 days c) 9.34 days d) 11.67 days

Answer 1

To determine how long a laboratory can wait to use a sample in an experiment while still having at least 10 percent of the original radioactivity, we need to calculate the number of half-lives that have elapsed. In this case, the half-life of P-32 is 14 days. The sample can be used after 1.67 half-lives or approximately 11.67 days.

Step-by-step explanation:

To determine how long a laboratory can wait to use a sample in an experiment while still having at least 10 percent of the original radioactivity, we need to calculate the number of half-lives that have elapsed. In this case, the half-life of P-32 is 14 days. We want to find the time when only 10 percent of the original radioactivity remains, which is equivalent to one-tenth of the initial amount. Since each half-life reduces the amount to half, we can calculate the number of half-lives by dividing the original radioactivity by 10. In this case, the sample can be used after 1.67 half-lives or approximately 11.67 days. Therefore, the correct answer is option d) 11.67 days.