Unit 4: Wave Models and Quantum Physics

A focused answer to the WACE Year 12 Physics Unit 4 dot point on atomic and nuclear physics. Energy levels and spectra, the Standard Model, mass-energy equivalence, mass defect and binding energy, and nuclear reactions.

A focused answer to the WACE Year 12 Physics Unit 4 content point on atomic models. The Rutherford nuclear model, its instability problem, Bohr's quantised orbits, photon emission and absorption between energy levels, and how de Broglie waves justify quantisation.

A focused answer to the WACE Year 12 Physics Unit 4 content point on atomic spectra. How discrete energy levels produce line spectra, the difference between emission and absorption spectra, why each element is unique, and using spectra to identify elements.

A focused answer to the WACE Year 12 Physics Unit 4 content point on diffraction gratings. The grating equation, why many slits give sharp bright maxima, how a grating disperses white light into a spectrum, and finding wavelengths from the diffraction angle.

A focused answer to the WACE Year 12 Physics Unit 4 dot point on light as a wave. Diffraction, Young's double-slit interference and the path-difference condition, fringe spacing, and the electromagnetic spectrum.

A focused answer to the WACE Year 12 Physics Unit 4 content point on mass-energy equivalence. The meaning of E=mc^2, the unified atomic mass unit, converting a mass defect into energy, and the link to relativistic energy at high speed.

A focused answer to the WACE Year 12 Physics Unit 4 content point on fission and fusion. How splitting heavy nuclei and joining light nuclei both move toward the binding-energy peak, chain reactions, the conditions fusion requires, and where each occurs.

A focused answer to the WACE Year 12 Physics Unit 4 content point on nuclear stability. The strong nuclear force, mass defect and binding energy, binding energy per nucleon, the shape of the binding-energy curve, and why fission and fusion release energy.

A focused answer to the WACE Year 12 Physics Unit 4 content point on accelerators and cosmology. How accelerators use electric and magnetic fields to create new particles, the energy-mass link, and the Big Bang evidence from the expanding universe and cosmic background radiation.

A focused answer to the WACE Year 12 Physics Unit 4 content point on polarisation. Why only transverse waves can be polarised, how polarising filters work, what happens when two filters are crossed, and everyday applications like polarising sunglasses.

A focused answer to the WACE Year 12 Physics Unit 4 content point on radioactivity. The three types of decay and their nuclear equations, the random nature of decay, half-life and the exponential decay of activity, and balancing nuclear equations.

A focused answer to the WACE Year 12 Physics Unit 4 content point on special relativity. Einstein's two postulates, the Lorentz factor, time dilation and length contraction, the proper-frame quantities, and evidence from fast-moving muons.

A focused answer to the WACE Year 12 Physics Unit 4 content point on standing waves. How superposition of waves travelling in opposite directions forms nodes and antinodes, the harmonic series on strings and in pipes, and the condition for resonance.

A focused answer to the WACE Year 12 Physics Unit 4 content point on the electromagnetic spectrum. The common nature of all EM waves, the wave equation linking frequency and wavelength, the ordering of the regions, and how photon energy varies across the spectrum.

A focused answer to the WACE Year 12 Physics Unit 4 dot point on the photoelectric effect. Photon energy, work function, threshold frequency, Einstein's photoelectric equation, stopping voltage and why the wave model fails.

A focused answer to the WACE Year 12 Physics Unit 4 content point on the Standard Model. The division into quarks and leptons, how quarks build protons and neutrons, the four fundamental forces and their carrier particles, and antimatter.

A focused answer to the WACE Year 12 Physics Unit 4 dot point on wave motion and superposition. The wave equation, the principle of superposition, standing waves on strings and in pipes, resonance and beats.

A focused answer to the WACE Year 12 Physics Unit 4 content point on wave-particle duality. How light shows both wave and particle behaviour, de Broglie's matter waves, the wavelength equation, and electron diffraction as evidence for the wave nature of matter.

A focused answer to the WACE Year 12 Physics Unit 4 content point on two-slit interference. Coherent sources, path difference conditions for bright and dark fringes, the fringe-spacing equation, and why the experiment supports the wave model of light.