Calculate the time required for the activity of a 9.0-mCi cobalt-60 source to decay to 8.5-mCi .The half-life of cobalt-60 is 5.26 years.

Question

Quizplus · Accepted Answer

Using the formula for radioactive decay:

A = A0 * (1/2)^(t/t1/2)

where A0 is the initial activity (9.0 mCi), A is the activity at time t, t1/2 is the half-life (5.26 years), and t is the time in years.

We can rearrange this formula to solve for t:

t = t1/2 * log(A/A0) / log(1/2)

t = 5.26 * log(8.5/9.0) / log(1/2)

t ≈ 0.442 years ≈ 5.2 months

Therefore, the time required for the activity of the cobalt-60 source to decay from 9.0 mCi to 8.5 mCi is approximately 5.2 months. Therefore, the best answer choice is C.

Calculate the Time Required for the Activity of a 9