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WAPhysics← Physics syllabus

Unit 4: Wave Models and Quantum Physics

19 dot points, in syllabus order. Each dot point has a focused answer, with exam-style questions and worked answers where available.

How do atomic energy levels and nuclear reactions release and reveal energy?

Explain atomic energy levels and spectra, the Standard Model, mass-energy equivalence and nuclear reactions

Atomic and nuclear physics. Energy levels and spectra, the Standard Model, mass-energy equivalence, mass defect and binding energy, and nuclear reactions.

How do fission and fusion release energy, and how do they differ?

Compare nuclear fission and fusion and explain the energy released using binding energy

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.

Why are some nuclei more stable than others, and what holds a nucleus together?

Explain nuclear binding energy and the stability of nuclei using the binding-energy curve

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.

How does polarisation show that light is a transverse wave?

Explain polarisation of light and how it provides evidence that light is a transverse wave

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.

How do reflected waves superpose to form standing waves and resonance?

Explain standing waves on strings and in pipes and relate harmonics to resonance

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.

How can both light and matter show wave and particle behaviour?

Explain wave-particle duality and apply the de Broglie wavelength to matter

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.

How do particle accelerators probe matter and support the Big Bang theory?

Explain how particle accelerators reveal fundamental particles and support the Big Bang model

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.

How does the photoelectric effect reveal the particle nature of light?

Explain the photoelectric effect using photons, work function, threshold frequency and Einstein's equation

Photoelectric effect. Photon energy, work function, threshold frequency, Einstein's photoelectric equation, stopping voltage and why the wave model fails.

How are the regions of the electromagnetic spectrum related and produced?

Describe the electromagnetic spectrum and relate frequency, wavelength and the speed of light

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.

How does the Standard Model classify the fundamental particles and forces?

Describe the Standard Model of particles, including quarks, leptons and the fundamental forces

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.

How did the Bohr model explain quantised atomic energy levels?

Describe the development of atomic models and explain quantised electron energy levels

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.

Why does each element produce a unique pattern of spectral lines?

Explain how emission and absorption line spectra arise from atomic energy levels

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.

How do unstable nuclei decay, and how does half-life describe the rate?

Describe alpha, beta and gamma decay and apply the concept of half-life to radioactive decay

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.

How does light behave as a wave through diffraction and interference?

Explain diffraction, two-slit interference and the electromagnetic spectrum as evidence for the wave model of light

Light as a wave. Diffraction, Young's double-slit interference and the path-difference condition, fringe spacing, and the electromagnetic spectrum.

How does Einstein's mass-energy equivalence explain energy released in nuclear reactions?

Apply mass-energy equivalence to calculate energy changes in nuclear reactions

WACE Year 12 Physics Unit 4 content point on mass-energy equivalence. The meaning of Einstein's mass-energy relation, the unified atomic mass unit, converting a mass defect into energy, and the link to relativistic energy at high speed.

How do time and length change for observers in relative motion at high speed?

Apply special relativity to time dilation and length contraction at high relative speeds

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.

How does a diffraction grating separate light into sharp, well-resolved spectral lines?

Apply the diffraction grating equation to analyse the dispersion of light into spectra

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.

How does the wave model describe motion, superposition and standing waves?

Apply the wave model to the wave equation, superposition, standing waves, resonance and beats

Wave motion and superposition. The wave equation, the principle of superposition, standing waves on strings and in pipes, resonance and beats.

How does Young's double-slit experiment provide evidence for the wave model of light?

Apply path difference and the double-slit equation to analyse two-source interference of light

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.