Assignment Chapter 10

3. A sample of radioactive polonium-214 produces alpha particles at a rate of 150 MBq. What

will be the rate of production of alpha particles in 3.69 X 10^-4 s? (3 marks)

4. A 30.2 g sample of magnesium-29 has a half of 9.5 minutes. How much magnesium is left in

47.5 minutes? (3 marks)

5. The radioactivity of a sample has decreased to one thirty second of its original value in

2.048 X 10³ s.

a) What is the half life of the element? (2 marks)

b) If the final mass was 18 g, what was the starting mass? (2 marks)

6. A sample of a living tree produces radioactivity of 0.45 Bq when tested for carbon-14. A tree

of the same species found in a lava flow has a reading of 0.080 Bq. How long ago did the

volcano erupt? (2 marks)

7. Write equations for each of these nuclear reaction. (2 marks each)

a) Calcium is bombarded with alpha particles to produce a nuclear reaction.

b) ⁵⁹Co²⁷ is bombarded with neutrons.

c) ⁶³Co²⁷ emits an alpha particle.

d) A neutron strikes a ²³⁹U⁹² atom which splits into a ²⁰⁷Pb⁸² atom. Also released are

eight neutrons and one beta particle.

e) A beryllium atom collides with a lithium atom. This results in the fusing of the two

atoms and the release of a beta particle and a neutron.

8. A nuclear reaction produces 4.8 X 10¹⁴ J of energy. How much mass was converted to

energy? (3 marks)

9. In a nuclear reaction, 4.7 X 10^-5 kg of mass disappears. How much energy was produced?

(3 marks)

10. An object receives a dosage of 50.2 Gy. How many Joules of energy has the object

absorbed if its mass is 30.0 kg. (3 marks)

January 20, 2014