10 free IGCSE Physics Nuclear Physics questions written in the style of Cambridge Physics papers: 3 multiple-choice and 7 structured, each with its answer and mark scheme. 4 of them are A* challenge questions, built to catch the mistakes strong students still make.
This topic covers The nuclear model of the atom, Radioactivity & half-life. Work through the questions below, then generate a full Nuclear Physics paper with a fresh set every time.
Generate a full Nuclear Physics paper →In the alpha-particle scattering experiment, alpha particles are fired at a thin sheet of gold foil.
1 Some alpha particles are deflected because they are attracted by the nucleus.
2 The results show that electrons orbit in fixed shells.
3 The experiment must be done in a vacuum so the alpha particles are not absorbed by air.
Which statements are correct?
Answer: D
A detector near a radioactive source records 660 counts per minute. The background count rate is 20 counts per minute. The half-life of the source is 6 hours.
What count rate does the detector record 18 hours later?
Answer: C
Which radiation is the most ionising?
Answer: B
A student measures the count rate from a radioactive source every 2 hours. The background count rate is 25 counts/min. Table 4.1 shows the measured count rates, which have not been corrected for background radiation.
| time / hours | 0 | 2 | 4 | 6 | 8 | 10 | 12 |
|---|---|---|---|---|---|---|---|
| measured count rate / counts/min | 985 | 704 | 505 | 364 | 265 | 195 | 145 |
Explain why the student must correct for background radiation before finding the half-life.
Use the data to determine the half-life of the source. Show your working.
Predict the measured count rate at time 20 hours.
The source emits beta particles. Suggest how the student could show that it does not also emit alpha particles.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | The measured count includes background, which does not halve; only the count from the source halves every half-life background radiation is included in every reading B1 background does not decrease, so halving the measured rate gives the wrong time B1 | 2 |
| (b) | 4 hours corrected initial rate = 985 − 25 = 960 C1 time for corrected rate to fall to 480 (measured 505) C1 4 A1 | 3 |
| (c) | 55 counts/min 5 half-lives: 960 ÷ 32 = 30 C1 add background: 55 A1 | 2 |
| (d) | Place a sheet of paper between source and detector; if the count rate does not fall, no alpha particles are emitted paper (or a few cm of air) between source and detector B1 no drop in count rate shows no alpha B1 | 2 |
In the alpha-particle scattering experiment, alpha particles were fired at a thin gold foil.
Describe what was observed.
State what each observation shows about the atom.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | most passed through; some deflected; few bounced back most alpha particles passed straight through B1 some were deflected through small angles B1 a very few were deflected back (through large angles) B1 | 3 |
| (b) | mostly empty space; small dense positive nucleus most of the atom is empty space B1 the mass and positive charge are concentrated in a tiny nucleus B1 | 2 |
Radioactive isotopes have many uses.
Explain why a gamma source is used to sterilise medical equipment.
Explain why an alpha source is used in smoke detectors.
Explain why a beta source is used to monitor the thickness of paper.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | penetrates packaging; kills bacteria gamma rays penetrate the packaging B1 and kill bacteria B1 | 2 |
| (b) | ionises air; stopped by smoke; short range safe alpha particles ionise the air so a current flows B1 smoke absorbs the alpha particles, reducing the current (and alpha has a short range) B1 | 2 |
| (c) | partly absorbed; count rate changes with thickness beta is partly absorbed by paper B1 changes in thickness change the count rate detected B1 | 2 |
A nucleus can be represented using nuclide notation.
Explain the meaning of the proton number and the nucleon number.
State the number of neutrons in ¹⁴₆C.
Explain why carbon-12 and carbon-14 are isotopes.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | Z protons; A protons + neutrons proton number: number of protons B1 nucleon number: total number of protons and neutrons B1 | 2 |
| (b) | 8 8 B1 | 1 |
| (c) | same protons, different neutrons same number of protons (6) but different numbers of neutrons B1 | 1 |
This question is about the nucleus.
In the alpha-particle scattering experiment, most alpha particles passed straight through gold foil and a very few bounced back. State what each observation shows about the atom.
A nucleus of radium-226 has proton number 88. State the number of neutrons.
Radium-226 decays by alpha emission to radon. Write the nuclide equation for the decay.
State what happens in a nucleus during beta decay.
Explain the difference between nuclear fission and nuclear fusion.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | most of atom is empty space; small dense positively charged nucleus most of the atom is empty space B1 mass and positive charge are concentrated in a very small nucleus B1 | 2 |
| (b) | 138 138 B1 | 1 |
| (c) | 22688Ra → 22286Rn + 42He alpha particle as 42He / α B1 nucleon number of product 222 B1 proton number of product 86 B1 | 3 |
| (d) | neutron changes into a proton and an electron; electron emitted a neutron changes into a proton B1 and an electron (beta particle) is emitted from the nucleus B1 | 2 |
| (e) | fission: large nucleus splits; fusion: small nuclei join fission: a large (unstable) nucleus splits into two smaller nuclei B1 fusion: two light nuclei join to form a heavier nucleus B1 | 2 |
This question is about uses of radioactive sources.
Name the three types of nuclear radiation and give a material that stops each.
A factory uses a radioactive source to monitor the thickness of paper. Explain which type of source should be used.
State and explain why a source used to monitor the thickness of paper in a factory should have a long half-life.
Explain why ionising radiation is harmful to living cells.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | alpha: paper; beta: aluminium; gamma: thick lead alpha: paper / skin B1 beta: a few mm of aluminium B1 gamma: several cm of lead / thick concrete B1 | 3 |
| (b) | beta: alpha stopped by paper, gamma passes regardless; beta partly absorbed, count depends on thickness Any 3 of: beta; alpha would be completely absorbed by the paper; gamma would pass through with almost no change; the beta count changes with thickness B3 | 3 |
| (c) | activity stays constant, need not be replaced the count rate does not fall noticeably over time B1 so changes in count are due to thickness / source need not be replaced often B1 | 2 |
| (d) | ionises molecules, damages DNA, can cause cancer or kill cells ionisation damages molecules / DNA in cells B1 can cause mutations / cancer or kill cells B1 | 2 |
A radioactive source emits alpha, beta and gamma radiation.
State which radiation is the most ionising and which is the most penetrating.
Describe how you could show that the source emits beta radiation, using a detector and absorbers.
State one safety precaution when handling radioactive sources.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | alpha; gamma most ionising: alpha B1 most penetrating: gamma B1 | 2 |
| (b) | paper then aluminium measure the count rate B1 place paper in front (stops alpha) B1 if the count rate falls further when a few mm of aluminium is added, beta is present B1 | 3 |
| (c) | tongs; keep distance; short time use tongs / keep the source at a distance / minimise exposure time / store in a lead box B1 | 1 |
In the 0625 syllabus, Nuclear Physics covers The nuclear model of the atom, Radioactivity & half-life.
This page has 10 Nuclear Physics questions with answers. For more, the free generator on mentorriyaz.in builds a new Nuclear Physics paper with a full mark scheme each time you click.
Riyaz Shaikh has mentored IGCSE, IB and A Level students for 15+ years, one-on-one, online and in Mumbai. The hardest questions on this site are the ones he uses to find a student's weak points.
Meet Riyaz →Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in