Question

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

Answer 1

1,868 years

Step-by-step explanation:

Answer 2

C 1,868 years

Step-by-step explanation:

I just took the test - I tried doing the math and was close but couldn't get it exact; so I guessed and I was correct :)