Lesson 6.4.4

6.4.4 Nuclear fission and fusion Quiz: OCR Physics, Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 6.4.4, Nuclear fission and fusion: 20 multiple choice questions for the OCR Physics (H156), Unit 5: Particles and medical physics, written with Revision Ninja.

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The 20 questions

  1. What represents the minimum energy required to completely separate a nucleus into its constituent nucleons?

    • Binding energy
    • Rest energy
    • Mass defect
    • Ionisation energy

  2. What is the primary function of a moderator in a thermal nuclear reactor?

    • Absorb fast neutrons
    • Control reaction rate
    • Slow down neutrons
    • Cool the reactor

  3. Which component in a nuclear fission reactor absorbs neutrons to control the rate of reaction?

    • Control rods
    • Coolant
    • Fuel rods
    • Moderator

  4. Which phenomenon occurs when a particle and its antiparticle meet and convert entirely into photons?

    • Nuclear fusion
    • Induced fission
    • Pair production
    • Annihilation

  5. What is the minimum total photon energy required to produce an electron-positron pair?

    • 2.04 MeV
    • 1.02 MeV
    • 13.6 eV
    • 0.51 MeV

  6. What term describes the difference between the total mass of individual nucleons and the bound nucleus mass?

    • Atomic mass
    • Mass defect
    • Mass number
    • Binding energy

  7. On a graph of binding energy per nucleon against nucleon number, which nuclide sits near the peak?

    • Uranium-235
    • Hydrogen-1
    • Helium-4
    • Iron-56

  8. Why does nuclear fusion require extremely high temperatures to occur?

    • Increase mass defect
    • Absorb excess neutrons
    • Overcome electrostatic repulsion
    • Overcome strong force

  9. Which equation links mass defect, speed of light, and binding energy?

    • E = mc
    • ΔE = Δm c²
    • E = hf
    • F = ma

  10. What happens to total binding energy when two light nuclei undergo nuclear fusion?

    • It increases
    • Becomes zero
    • It remains constant
    • It decreases

  11. What category of radioactive waste includes metal fuel cladding and reactor components?

    • Low-level waste
    • Exempt waste
    • Intermediate-level waste
    • High-level waste

  12. What material is commonly used as a moderator in graphite-moderated fission reactors?

    • Graphite
    • Lead
    • Boron
    • Cadmium

  13. What is the ultimate long-term disposal method for high-level nuclear radioactive waste?

    • Ocean dumping
    • Atmospheric release
    • Incineration
    • Geological disposal

  14. Which process releases energy by splitting a heavy nucleus into two smaller daughter nuclei?

    • Pair production
    • Induced fission
    • Beta decay
    • Nuclear fusion

  15. What energy unit is equivalent to 1.60 × 10⁻¹³ joules?

    • 1 GeV
    • 1 keV
    • 1 MeV
    • 1 eV

  16. What particle is absorbed by a uranium-235 nucleus to induce nuclear fission?

    • Alpha particle
    • Fast proton
    • Gamma photon
    • Thermal neutron

  17. What is the rest energy of a single electron in megaelectronvolts?

    • 0.51 MeV
    • 0.00 MeV
    • 1.02 MeV
    • 938 MeV

  18. When a heavy nucleus undergoes fission, how does the total mass of products compare to reactants?

    • Mass is lower
    • Mass is higher
    • Mass doubles
    • Mass is identical

  19. What happens to binding energy per nucleon for nuclei heavier than iron-56 as nucleon number increases?

    • It stays constant
    • It decreases
    • It increases
    • It reaches zero

  20. Which chemical element is commonly used to make control rods in a nuclear fission reactor?

    • Boron
    • Concrete
    • Uranium
    • Graphite

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