CIE A Level Physics
CIE A Level Physics Particle Physics Exam Questions
Free CIE A Level Physics exam questions for Particle Physics, with a mark scheme for every pack. Covers the nuclear atom, alpha-particle scattering, alpha, beta and gamma radiation, quarks, hadrons, leptons and beta decay.
Particle Physics exam questions
1 question pack of real past exam questions, each with its mark scheme. Do not stop after a few: answer as many as you can without notes, then mark every answer with the mark scheme. The more questions you do, the more quickly you will spot how examiners ask about each idea.
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A-Level Physics Flashcards for 2027 Onwards
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About CIE A Level Physics Particle Physics
Particle physics is Topic 11 of the Cambridge International AS & A Level Physics (9702) syllabus. It starts with the nuclear model of the atom and the alpha-particle scattering experiment, then covers the nature of alpha, beta and gamma radiation, nuclear equations and the electron-volt. The second part introduces fundamental particles: quarks, antiquarks, hadrons (baryons and mesons) and leptons, and explains beta decay in terms of quark changes. Nuclear physics at A Level builds on this. Examiners often ask for conclusions from alpha scattering, quark compositions and charges, and why a neutrino or antineutrino is needed in beta decay.
What you need to know
- Nuclear atom Alpha-particle scattering showed that most of the atom is empty space, with a small, dense, positively charged nucleus. Nucleon number A and proton number Z describe a nuclide; isotopes have the same Z but different numbers of neutrons.
- Types of radiation Alpha particles are helium nuclei; beta-minus particles are electrons and beta-plus particles are positrons; gamma radiation is electromagnetic. Know their charges, relative masses and ionising and penetrating abilities.
- Beta decay and neutrinos Beta-minus decay emits an electron antineutrino; beta-plus decay emits an electron neutrino. Beta particles have a continuous range of energies because energy is shared with the (anti)neutrino.
- Fundamental particles Quarks: up (+2/3 e), down (-1/3 e) and strange (-1/3 e), each with an antiquark of opposite charge. Leptons, such as electrons and neutrinos, are fundamental particles.
- Hadrons Baryons contain three quarks (proton uud, neutron udd); mesons contain a quark and an antiquark.
- Quark changes In beta-minus decay a down quark changes to an up quark; in beta-plus decay an up quark changes to a down quark.
Common mistakes in Particle Physics
- Saying alpha scattering showed electrons orbit the nucleus. It showed a small, massive, positive nucleus; most alpha particles passed straight through.
- Mixing up neutrinos and antineutrinos. Beta-minus decay produces an antineutrino; beta-plus produces a neutrino.
- Forgetting that antiquarks have the opposite charge. An anti-down quark has charge +1/3 e.
- Calling mesons fundamental particles. Mesons are hadrons made of a quark-antiquark pair.
- Not balancing both nucleon number and proton number in nuclear equations.
Try three Particle Physics exam-style questions
1. State two conclusions from the alpha-particle scattering experiment and the observation that supports each. (4 marks)
Show the mark scheme answer
Most of the atom is empty space; because most alpha particles passed straight through undeflected; the nucleus is very small and contains most of the mass and is positively charged; because a very small fraction were deflected through large angles.
2. Describe beta-minus decay in terms of quarks and write the particles emitted. (3 marks)
Show the mark scheme answer
A neutron (udd) changes to a proton (uud); a down quark changes to an up quark; an electron and an electron antineutrino are emitted.
3. A meson consists of an up quark and an anti-down quark. Determine its charge. (2 marks)
Show the mark scheme answer
Up = +2/3 e and anti-down = +1/3 e; total charge = +1e (+1.60 × 10^-19 C).
Particle Physics FAQs
What does Cambridge AS & A Level Physics Particle physics cover?
It covers the nuclear atom, alpha-particle scattering, alpha, beta and gamma radiation, nuclear equations, the electron-volt, quarks, hadrons, leptons and beta decay in terms of quarks.
Which papers is Particle physics examined in?
It is an AS Level topic assessed in Paper 1 and Paper 2, and it provides the background for Nuclear physics at A Level.
Which quark compositions do I need to know?
Learn the charges of up, down and strange quarks and their antiquarks, and that the proton is uud and the neutron is udd, so you can work out charges of other hadrons.
