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E. Nuclear and quantum physics

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  1. E.1 Structure of the atom

    1. • Geiger-Marsden-Rutherford experiment and the discovery of the nucleus.

    2. • Use nuclear notation: A = nucleon number, Z = proton number, X = element symbol.

    3. • Emission and absorption spectra provide evidence for discrete atomic energy levels.

    4. • Photons are emitted/absorbed during transitions between atomic energy levels.

    5. • Photon energy in atomic transition: E=hf.

    6. • Use emission and absorption spectra to infer chemical composition.

    7. • Nuclear radius scales with nucleon number: R=R0 A^(1/3); implies near-constant density. • Relationship implies approximately constant nuclear density.

    8. • Deviations from Rutherford scattering at high energies.

    9. • Use energy conservation for distance of closest approach in head-on scattering.

    10. • Bohr hydrogen energy levels: E=-13.6/n^2 eV.

    11. • Bohr quantization: angular momentum mvr = nh/(2π).

  2. E.2 Quantum physics

    1. • Photoelectric effect is evidence for particle nature of light.

    2. • Photoelectrons require photons above threshold frequency.

    3. • Photoelectric equation: Emax = hf - Φ.

    4. • Particle diffraction is evidence for wave nature of matter.

    5. • Matter exhibits wave-particle duality.

    6. • de Broglie wavelength: λ=h/p.

    7. • Compton scattering is evidence for particle nature of light.

    8. • Scattered photons have increased wavelength.

    9. • Compton shift: Δλ = h/(mec)(1-cosθ).

  3. E.3 Radioactive decay

    1. E.3.1—Isotopes

      • Isotopes.

    2. E.3.2—Binding energy and mass defect

      • Nuclear binding energy and mass defect. • Mass defect connects nuclear mass loss with binding energy.

    3. E.3.3—Binding energy curve

      • Use binding energy per nucleon variation with nucleon number.

    4. E.3.4—Mass-energy equivalence

      • Mass-energy equivalence in nuclear reactions: E=mc^2.

    5. E.3.5—Strong nuclear force

      • Strong nuclear force is short-range and attractive between nucleons.

    6. E.3.6—Random radioactive decay

      • Radioactive decay is random and spontaneous.

    7. E.3.7—Decay nuclear changes

      • Alpha, beta and gamma decays change nuclear state differently.

    8. E.3.8—Decay equations

      • Write radioactive decay equations for α, β-, β+ and γ.

    9. E.3.9—Neutrinos and antineutrinos

      • Existence of neutrinos ν and antineutrinos ν. • Neutrinos and antineutrinos are required in beta decay.

    10. E.3.10—Radiation penetration and ionization

      • Compare penetration and ionizing ability of α, β and γ radiation.

    11. E.3.11—Activity, count rate and half-life

      • Activity, count rate and half-life in radioactive decay.

    12. E.3.12—Half-life changes

      • Use integer half-lives to track activity and count rate changes.

    13. E.3.13—Background radiation

      • Effect of background radiation on count rate. • Correct count rate for background radiation.

    14. E.3.14 (HL)—Evidence for strong force

      • Evidence supports the strong nuclear force.

    15. E.3.15 (HL)—Neutron-proton ratio

      • Neutron-to-proton ratio affects nuclide stability.

    16. E.3.16 (HL)—Binding energy above A≈60

      • Binding energy per nucleon is approximately constant above A≈60.

    17. E.3.17 (HL)—Discrete nuclear energy levels

      • Alpha and gamma spectra show discrete nuclear energy levels.

    18. E.3.18 (HL)—Beta spectrum and neutrino

      • Continuous beta spectrum is evidence for the neutrino.

    19. E.3.19 (HL)—Radioactive decay law

      • Radioactive decay law: N=N0e^(-λt).

    20. E.3.20 (HL)—Decay constant meaning

      • Decay constant approximates unit-time decay probability when λt is very small.

    21. E.3.21 (HL)—Activity equation

      • Activity is decay rate: A=λN=λN0e^(-λt).

    22. E.3.22 (HL)—Half-life and decay constant

      • Half-life relation: T1/2 = ln2/λ.

  4. E.4 Fission

    1. • Energy is released in spontaneous and neutron-induced fission.

    2. • Chain reactions sustain nuclear fission.

    3. • Know control rods, moderators, heat exchangers and shielding in nuclear power plants. • Control rods, moderators, heat exchangers and shielding each have distinct roles.

    4. • Know fission products and nuclear waste management issues. • Include properties and management of fission products.

  5. E.5 Fusion and stars

    1. • Stars are stable when outward radiation pressure balances inward gravity.

    2. • Fusion is a source of energy in stars.

    3. • Fusion in stars requires high density and temperature.

    4. • Stellar mass determines star evolution pathway.

    5. • Use HR diagram regions to describe star properties. • Include main sequence, red giants/supergiants, white dwarfs and lines of constant radius.

    6. • Stellar parallax distance: d(pc)=1/p(arcsec).

    7. • Determine stellar radius from luminosity and surface temperature.