Module 7: The Nature of Light
8 dot points across 3 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.
Inquiry Question 1: What is light?
A focused answer to the HSC Physics Module 7 dot point on the electromagnetic spectrum. Frequency, wavelength and photon energy across radio to gamma rays, the relations c = f lambda and E = hf, and how Maxwell's equations conceptually predict EM waves at the speed of light.
A focused answer to the HSC Physics Module 7 dot point on the wave model of light. Young's double-slit interference with d sin theta = m lambda, single-slit diffraction, polarisation as evidence light is transverse, and quantitative use of Malus's law.
Inquiry Question 3: What evidence supports the relativistic model of the universe?
A focused answer to the HSC Physics Module 7 dot point on evidence for special relativity. Atmospheric muon flux at sea level, accelerator muon lifetimes, the daily GPS clock corrections (combined SR and GR), and the routine use of relativistic mechanics in particle physics.
A focused answer to the HSC Physics Module 7 dot point on light and special relativity. The Michelson-Morley null result, Einstein's two postulates, and quantitative application of time dilation t = gamma t_0, length contraction L = L_0 / gamma and relativity of simultaneity.
A focused answer to the HSC Physics Module 7 dot point on mass-energy equivalence. The total relativistic energy E = gamma m c^2, the rest energy E_0 = mc^2, mass defect Delta m in nuclear binding, and worked examples for fission, fusion and the deuteron binding energy.
A focused answer to the HSC Physics Module 7 dot point on relativistic momentum. Why p = mv fails near c, the relativistic form p = gamma m v, the relativistic energy-momentum relation E^2 = (pc)^2 + (mc^2)^2, and how this drives the design of particle accelerators.
Inquiry Question 2: What is observed when light interacts with matter?
A focused answer to the HSC Physics Module 7 dot point on the quantum model of light. Photon energy E = hf, Einstein's photoelectric equation hf = phi + K_max, Planck's constant, threshold frequency and stopping voltage, and why the wave model cannot explain the observations.
A focused answer to the HSC Physics Module 7 dot point on spectroscopy. Continuous, emission-line and absorption-line spectra explained by quantised atomic energy levels, plus how stellar spectra reveal chemical composition, surface temperature, rotation and radial velocity (Doppler shift).