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 explain that all matter turns some of its internal energy into electromagnetic radiation, and why hotter objects radiate more. (Guide: “Everything glows”)
- I can define a blackbody and explain why a body at constant temperature that absorbs radiation must also emit it. (Guide: “The blackbody model”)
- I can state that a blackbody’s spectrum is continuous and depends only on its temperature. (Guide: “The blackbody spectrum”; Practice Q7c)
- I can explain why classical physics failed at short wavelengths and what Planck assumed about light energy. (Guide: “Why classical physics failed”; Practice Q7d)
Calculation and skills
- I can sketch intensity per unit wavelength against wavelength for two temperatures, with the correct shape, order and peak positions. (Guide: Figure 1; Practice Q6)
- I can use λ_max = b/T to find a temperature or a peak wavelength, with T in kelvin and λ in metres. (Guide: Worked example 1; Practice Q1, Q5b, Q7a)
- I can use P = σAT⁴ to find the power, the area or the temperature of a blackbody. (Guide: Worked example 2; Practice Q5, Q7b)
- I can compare two blackbodies using ratios of T⁴ and of area. (Guide: Worked example 1; Practice Q3, Q4)
Reasoning
- I can justify that a hotter blackbody emits more at every wavelength and peaks at a shorter wavelength. (Practice Q2, Q6b)
- I can link the total power to the area under the curve. (Practice Q6c)
- I can explain the colours of hot objects and stars using where their curves peak. (Guide: “The blackbody spectrum”; Practice Q7c)
All ticked? Move on to Topic 15.5, The Photoelectric Effect, or return to the course roadmap.