Once the activity of americium in a smoke detector falls below 5 percent of its original activity, it's no longer able to effectively detect smoke and trigger the alarm. If the half-life of americium-241 is approximately 432.2 years, how many years will it take before the americium-241 is unable to detect smoke?
Question 11 options:
A)
10 years
B)
20 years
C)
1,868 years
D)
2 years