Work through the list without notes. If you cannot do a statement, follow its link, then come back. Guide = study guide; Practice = practice questions.
Understanding
- I can describe Compton scattering as a collision between a photon and a free electron at rest, in which the photon survives with less energy. (Guide: “A photon that bounces”)
- I can state what happens to a photon’s energy, frequency, wavelength, momentum and speed when it is scattered. (Guide: “The momentum of a photon”; Practice Q1)
- I can explain why a classical wave model predicts no wavelength shift, and why the observed shift is evidence for photons. (Guide: “A photon that bounces”; Practice Q7d)
- I can explain why the effect is studied with X-rays rather than visible light. (Guide: “The Compton shift equation”)
Calculation and skills
- I can use p = h/λ to find the momentum of a photon. (Guide: “The momentum of a photon”; Practice Q5d)
- I can use Δλ = (h/m_e c)(1 − cos θ) at any angle, including angles above 90°. (Guide: table; Practice Q2, Q3)
- I can use energy conservation to find the kinetic energy of the recoiling electron without rounding too early. (Guide: Worked example 1; Practice Q5)
- I can apply momentum conservation in x and y to find the electron’s momentum and direction. (Guide: Worked example 2; Practice Q6)
- I can choose axes that make Compton data linear and read λ and h/(m_e c) from the graph. (Practice Q7)
Reasoning
- I can draw before-and-after momentum diagrams for a scattering event, with the electron on the correct side. (Guide: Figure 1; Practice Q6a)
- I can compare two scattering events by angle or by starting wavelength, using absolute and fractional changes. (Guide: “Comparing scattering situations”; Practice Q4)
- I can explain why an electron can end up with more momentum than the incoming photon without breaking conservation of momentum. (Guide: Worked example 2; Practice Q6c)
All ticked? Move on to Topic 15.7, Fission, Fusion, and Nuclear Decay, or return to the course roadmap.