1) Calculate the rate of disintegration if the following:

1. 1. 1.0 * 10¹³ atoms ^99mTc.
   2. 1.0 * 10¹⁴ atoms ¹⁴C.
   3. 1.0 gram ²³⁹Pu.
   4. 1.0 gram ²³⁵U.

2) Calculate the amount of atoms of the following nuclei, based on their activity:

1. 1. 10 MBq of ³²P
   2. 200 kBq of ¹³¹I

3) A source of ⁶⁰Co has a rate of disintegration equal to 1.0 * 10¹⁴ Bq. What is the mass of ⁶⁰Co in grams?

4) A preparation labelled ³H disintegrates with 3.0 * 10⁵ Bq.

1. 1. What is the rate of disintegration after 3 years?
   2. How long does it take for the rate of disintegration to reach 2.0 * 10⁵ Bq?

5) A patient is administered 4.0 * 10⁷ Bq ^99mTc in connection with a nuclear medicine examination. Calculate the amount of mass of ^99mTc injected in the patient. The daughter nuclide ⁹⁹Tc is radioactive, but has a very long half-life. Show that the total rate of disintegration in the patient is insignificant one week after the examination.

6) Calculate the rate of disintegration of the following:

1. 1. 1.0 g natural Lu-metal
   2. 1.0 g natural Sm-metal

7) Recently it was showed that natural Bi is radioactive. How much amount of Bi is required to give a disintegration rate of 10 Bq?

8) In nature ²³⁴U exist in equilibrium with ²³⁸U as a daughter product.

1. 1. How much ²³⁸U has an equivalent disintegration rate as 1 g ²³⁴U?
   2. Given the amounts from a) is separated as pure ²³⁸U and ²³⁴U, how many percent has the amount of ²³⁸U decreased when the amount of ²³⁴U is halved?