Sodium-24 has a half-life of approximately 15 hours. If only one-eighth of the sodium-24 remains, about how much time has passed? a 15 hours b 30 hours c 60 hours d 45 hours

1 answer

The correct answer is d) 45 hours.

In one half-life of sodium-24, one-half of the original amount remains. Therefore, if one-eighth of the sodium-24 remains, we can determine how many half-lives have passed.

One-eighth is equal to (1/2)^3. This means that three half-lives have passed since one-eighth of the original amount remains.

Since each half-life is approximately 15 hours, we can multiply the number of half-lives (3) by the duration of each half-life (15 hours) to determine the total time that has passed.

3 x 15 = 45 hours

Therefore, about 45 hours have passed.