Question

In the preparation of a PET scan, a sample of the isotope ¹⁸F is acquired from the lab with an activity of 30.0 mCi at 10:00 am. What is the activity of the sample in becquerel at 3:00 pm (5.0 hours later), if the half-life of ¹⁸F is 2.0 hours?

2.73 x 10⁷ Bq

8.14 x 10⁸ Bq

6.19 x 10⁷ Bq

1.96 x 10⁸ Bq

4.52 x 10⁸ Bq

Answer 1

Ans:

Solution:

Given,

Initial activity

Half life

time .

The decay constant is given by,

....... (1)

The activity of the sample after hrs is given by,

We know, . Thus,