Lesson 8.3.1

8.3.1 Conservation of charge, energy and momentum in interactions Quiz: Pearson Edexcel Physics, Unit 8

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 8.3.1, Conservation of charge, energy and momentum in interactions: 20 multiple choice questions for the Pearson Edexcel Physics (9PH0), Unit 8: Nuclear and Particle Physics, written with Revision Ninja.

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The 20 questions

  1. Which set of quantities is conserved in every particle interaction?

    • Charge, energy, momentum
    • Charge, mass, speed
    • Momentum, force, mass
    • Energy, speed, force

  2. How does total electric charge before an interaction compare to total charge after?

    • Zero total charge
    • Equal total charge
    • Smaller initial charge
    • Greater initial charge

  3. What properties of a particle are determined from track curvature in a magnetic field?

    • Momentum and charge
    • Energy and radius
    • Mass and temperature
    • Speed and volume

  4. A neutron decays into a proton, electron, and antineutrino. What is the product charge?

    • Plus two
    • Minus one
    • Plus one
    • Zero

  5. What is the minimum total energy of the two photons produced when an electron and a positron at rest annihilate?

    • 0.511 MeV
    • 2.04 MeV
    • 0 MeV
    • 1.02 MeV

  6. An electron and positron at rest annihilate into two photons. What is the total final momentum?

    • Zero
    • mc
    • Infinite
    • 2 mc

  7. A stationary particle of rest energy 135 MeV decays into two photons of equal energy. What is the energy of each photon?

    • 67.5 MeV
    • 270 MeV
    • 33.8 MeV
    • 135 MeV

  8. A stationary particle decays into two identical particles. How do their momenta compare?

    • Equal and opposite
    • Zero for both
    • Proportional to mass
    • Equal and parallel

  9. Why can a single high-energy photon not produce a single electron in pair production?

    • Energy is not conserved
    • Charge is not conserved
    • Mass is too high
    • Momentum is zero

  10. What is the total lepton number before and after electron-positron annihilation?

    • Plus one
    • Plus two
    • Zero
    • Minus one

  11. A 2.0 MeV photon creates an electron-positron pair in the presence of a nucleus that absorbs the recoil momentum. What total kinetic energy is shared between the electron and positron?

    • 2.0 MeV
    • 0.51 MeV
    • About 0.98 MeV
    • 1.02 MeV

  12. Why is a nearby nucleus required for pair production in free space?

    • Charge is not conserved
    • Energy is insufficient
    • Lepton number is zero
    • Momentum is not conserved

  13. A proton and an antiproton, both at rest, annihilate. Approximately what total energy is released? Each has rest energy of about 0.94 GeV.

    • About 0.94 GeV
    • About 1.9 GeV
    • About 3.8 GeV
    • About 0.51 GeV

  14. A track in a bubble chamber has radius 0.50 m in a uniform magnetic field of flux density 0.30 T, for a particle of charge 1.6 x 10^-19 C. What is the momentum of the particle?

    • 2.4 x 10^-20 kg m s^-1
    • 3.2 x 10^-19 kg m s^-1
    • 1.2 x 10^-20 kg m s^-1
    • 4.8 x 10^-20 kg m s^-1

  15. Besides energy, which quantity must also be conserved for a particle interaction to occur?

    • Temperature
    • Charge
    • Velocity
    • Mass

  16. What is the total momentum of the decay products of a particle at rest?

    • Undefined
    • Equal to mass
    • Maximum
    • Zero

  17. Which conservation law forbids an electron from decaying into a single photon?

    • Parity conservation
    • Energy conservation
    • Charge conservation
    • Baryon conservation

  18. A pi-zero meson (charge 0) is produced in the collision p + p -> p + p + pi0. What is the total charge after the collision?

    • 0
    • +3
    • +1
    • +2

  19. A particle at rest with rest energy 1000 MeV decays into two particles. One of them has energy 600 MeV. What is the energy of the other?

    • 300 MeV
    • 1600 MeV
    • 600 MeV
    • 400 MeV

  20. Which conservation law forbids a proton from decaying into a positron and a neutral pion?

    • Energy
    • Lepton number
    • Baryon number
    • Charge

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