Atomic Physics IGCSE

People working with radioactive materials use a photographic film badge covered in paper. The badge is used to monitor the level of their exposure to radiation.

Which radiation is detected?

• alpha-particles only

• beta-particles only

• gamma-rays and beta-particles

• gamma-rays only

The results of the Geiger-Marsden scattering experiment provided evidence for the presence of

the nucleus within the atom.

What were scattered in this experiment?

• alpha-particles

• beta-particles

• gamma rays

• gold nuclei

The diagram shows how the thickness of paper is measured during manufacture.

If the sheet is too thick, fewer beta-particles can reach the detector.

A source of alpha-particles is not used for this purpose because alpha-particles

• are all stopped by the paper.

• are too dangerous to those working nearby.

• have a short half-life.

• make the paper radioactive

A radioactive isotope has a half-life of 2 minutes.

What can be deduced from this statement?

• After ½ minute, ¼ of the isotope remains.

• After 1 minute, ¼ of the isotope remains.

• After 4 minutes, ¼ of the isotope remains.

• After 4 minutes, none of the isotope remains.

In a fission reactor, which particle causes a Uranium-235 nucleus to split?

• alpha-particle

• gamma ray

• neutron

• proton

Three nuclei P, Q and R have proton numbers (atomic numbers) and nucleon numbers (mass numbers) as shown.

Which nuclei are isotopes of the same element?

• P and Q only

• P and R only

• Q and R only

• P, Q and R

The nucleus of a nitrogen atom can be represented as (_7^14)N .

The nucleus of this atom consists of

• 7 protons and 7 electrons.

• 7 protons and 7 neutrons.

• 14 protons and 7 electrons.

• 14 protons and 7 neutrons.

X, Y and Z are three types of radiation.

X is almost completely absorbed by 5 cm lead but not by 5 mm aluminium.

Y is almost completely absorbed by 5 mm aluminium but not by thin card.

Z is absorbed by thin card.

What are X, Y and Z?

• A

• B

• C

• D

Ra decays with a half-life of 1600 s.

Rn decays with a half-life of 52 s.

Po decays with a half-life of 9.1 s.

Pb decays with a half-life of 10.6 h.

The changing count rate for one of these radioactive nuclides is shown in the graph.

From the half-life shown by the graph, which was the decaying radioactive nuclide?

• Ra

• Rn

• Po

• Pb

A narrow beam of alpha-particles is fired at a thin piece of gold foil.

Which is the final direction of the largest number of alpha-particles?

• A

• B

• C

• D