O Level Combined Science 5129 · Topic 27

Nuclear physics: past paper questions

57 real questionsasked in 7 of the last 10 exam series2020–2025usually: State, Explain, Suggest, Describe, Determine

Real questions on nuclear physics

The newest 20 of 29 written questions, plus 28 multiple-choice. Open one to see it on the real paper.

5129/22 · October/November 2025 · Q14a[2]
The time taken for the counter reading to halve is the half-life. On Fig. 14.1, draw one horizontal line and one vertical line to show how the half-life of the radioactive source can be determined. Record the value of the half-life determined using the lines that you have drawn. half-life = days
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5129/22 · October/November 2025 · Q14b[2]
Radioactive sources are used in smoke alarms. State two other uses of radioactive sources.
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5129/22 · October/November 2025 · Q14c[2]
Describe two precautions for the safe handling of radioactive sources.
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5129/22 · May/June 2024 · Q13a[2]
The time taken for the counter reading to halve is the half-life. On Fig. 13.2 draw one horizontal line and one vertical line to show how the half-life of the radioactive source is determined from the graph. Record the value of the half-life found using the lines that you have drawn. half-life = minutes
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5129/22 · May/June 2024 · Q13b[1]
Explain why the background count rate must be removed from the counter reading before determining the half-life of the source.
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5129/22 · May/June 2024 · Q13c[1]
At the start of the experiment, the teacher uses a pair of forceps with a long handle to move the radioactive source as shown in Fig. 13.3. pair of forceps with long handle radioactive source Fig. 13.3 Explain why the teacher needs to use a pair of forceps with a long handle.
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5129/21 · October/November 2023 · Q9[4]
During an earthquake, two types of seismic wave are transmitted through the Earth. State the names of these two types of seismic wave. Describe the difference between these two types of seismic wave and compare how they transfer energy. You may draw a labelled diagram if it helps you with your description.
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5129/22 · October/November 2023 · Q16c(i)[2]
Explain what is meant by ‘half-life’.
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5129/22 · October/November 2023 · Q16c(ii)[1]
Suggest which isotope in Table 16.1 is most useful in a factory where food is exposed to radiation.
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5129/21 · May/June 2023 · Q16a[1]
Describe the particle that is emitted from the nucleus when the isotope decays.
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5129/21 · May/June 2023 · Q16b(i)[1]
Suggest why emitters used inside the body have a short half‑life.
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5129/21 · May/June 2023 · Q16b(ii)[1]
Suggest one other type of emission that can be used safely inside the body.
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5129/22 · May/June 2023 · Q16[3]
Fig. 16.1 shows some of the apparatus used to determine the types of emissions from a radioactive source. 2202 radioactive source detector counter Fig. 16.1 Describe how additional apparatus is used to show that the source emits gamma radiation.
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5129/21 · October/November 2022 · Q12a(i)[1]
Identify the energy store in the radioactive source. Tick (3) one box. chemical electrical kinetic nuclear sound
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5129/22 · October/November 2022 · Q16a[2]
Alpha-particles are one type of emission. Suggest one feature of alpha-particles that explains why they are the most ionising type of radiation. feature explanation
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5129/22 · October/November 2022 · Q16b[1]
State one other type of radioactive emission.
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5129/22 · October/November 2022 · Q16c[1]
Explain why some types of emission lead to the formation of new elements.
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5129/22 · October/November 2022 · Q16d[1]
Explain why waste radioactive materials are encased in concrete and stored deep underground for many years.
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5129/22 · May/June 2022 · Q19a[2]
Determine the nucleon number and proton number of the particle emitted from the uranium nucleus. nucleon number of emitted particle proton number of emitted particle
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5129/22 · May/June 2022 · Q19b[1]
Thorium is also radioactive. It decays to an isotope of protactinium by the emission of a beta-particle. On Fig. 19.1 plot the position of this protactinium isotope. Label this point Pa.
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What examiners said

Only a few candidates appeared to be familiar with this new syllabus content. Many recalled that waves are either longitudinal or transverse. A few knew that seismic waves are either p-waves or s-waves. Many candidates referred to ‘shock waves’, which is not a phrase used in this syllabus. The most able candidates also explained that these waves transfer energy and are carried by vibrations that a...
— Examiner report, October/November 2023, 5129/21 Q9 (Cambridge)

Most candidates knew that half-life is a measure of time. However, only the most able candidates referred to half of the nuclei of the isotope decaying.
— Examiner report, October/November 2023, 5129/22 Q16(c)(i) (Cambridge)

Many candidates selected technetium. However, with a 6 hour half-life, there would only be the slightest trace left in two days. The factory would need an isotope that does not need to be replaced frequently.
— Examiner report, October/November 2023, 5129/22 Q16(c)(ii) (Cambridge)

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In the syllabus

27.1 The nuclear model of the atom

Describe the structure of the atom in terms of a positively charged nucleus and negatively charged electrons in orbit around the nucleus
Describe the composition of the nucleus in terms of protons and neutrons
Define the terms (a) proton number / atomic number, Z (b) nucleon number / mass number, A and be able to calculate the number of neutrons in a nucleus
Explain what is meant by an isotope and state that an element may have more than one isotope

27.2 Radioactivity

Describe the detection of alpha particles (α-particles) using a cloud chamber or spark counter, and the detection of beta particles (β-particles) (β-particles will be taken to refer to β−) and gamma radiation (γ-radiation) by using a Geiger-Müller (GM) tube and counter
Use count rate measured in counts / s or counts / minute
Know what is meant by background radiation Know that radioactive decay is a change in an unstable nucleus that can result in the emission of α, β and γ radiation and know that these changes are spontaneous and random Describe α-particles as two protons and two neutrons (helium nuclei), β-particles as high-speed electrons from the nucleus and γ-radiation as high-frequency electromagnetic waves State, for α-particles, β-particles and γ-radiation: (a) their relative ionising effects (b) their relative penetrating powers Define the half-life of a particular isotope as the time taken for half the nuclei of that isotope in any sample to decay Explain how the type of radiation emitted and the half-life of the isotope determine which isotope is used for applications including: (a) household fire (smoke) alarms (b) irradiating food to kill bacteria (c) sterilisation of equipment using gamma rays (d) measuring and controlling thicknesses with the choice of radiations used linked to penetration and absorption (e) diagnosis and treatment of cancer using gamma rays Explain how radioactive materials are moved, used and stored in a safe way, with reference to: (a) reducing exposure time (b) increasing distance between source and living tissue (c) use of shielding to absorb radiation

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