How long will it take a 4.50-kBq sample of material to reach an activity level of 0.140 kBq if the half-life of the sample is 435 years?

Question

Quizplus · Accepted Answer

The equation for radioactive decay is:

A = A0 (1/2)^(t/T)

where A is the final activity level, A0 is the initial activity level, t is time, T is the half-life.

Plugging in the values given in the problem:

0.140 kBq = 4.50 kBq (1/2)^(t/435)

Solving for t:

t = 2178 years

How Long Will It Take a 4