E. Nuclear and quantum physics

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

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

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

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

• Photon energy in atomic transition: E=hf.

• Use emission and absorption spectra to infer chemical composition.

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

• Deviations from Rutherford scattering at high energies.

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

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

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

• Photoelectric effect is evidence for particle nature of light.

• Photoelectrons require photons above threshold frequency.

• Photoelectric equation: Emax = hf - Φ.

• Particle diffraction is evidence for wave nature of matter.

• Matter exhibits wave-particle duality.

• de Broglie wavelength: λ=h/p.

• Compton scattering is evidence for particle nature of light.

• Scattered photons have increased wavelength.

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

• Isotopes.

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

• Use binding energy per nucleon variation with nucleon number.

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

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

• Radioactive decay is random and spontaneous.

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

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

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

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

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

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

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

• Evidence supports the strong nuclear force.

• Neutron-to-proton ratio affects nuclide stability.

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

• Alpha and gamma spectra show discrete nuclear energy levels.

• Continuous beta spectrum is evidence for the neutrino.

• Radioactive decay law: N=N0e^(-λt).

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

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

• Half-life relation: T1/2 = ln2/λ.

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

• Chain reactions sustain nuclear fission.

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

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

E.5.1—Stellar equilibrium

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

E.5.2—Fusion in stars

• Fusion is a source of energy in stars.

E.5.3—Fusion conditions

• Fusion in stars requires high density and temperature.

E.5.4—Stellar mass and evolution

• Stellar mass determines star evolution pathway.

E.5.5—HR diagram regions

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

E.5.6—Stellar parallax

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

E.5.7—Stellar radii

• Determine stellar radius from luminosity and surface temperature.