HOTTER = MORE and SHORTER:
- MORE radiation emitted per second
- SHORTER peak wavelength
For surfaces — think of sunbathing: A black t-shirt gets hotter in the sun than a white one (absorbs more). The same dark fabric would also cool down faster at night (emits more). Good absorber = good emitter.
Acronym — BEAD:
- Black body absorbs everything
- Emits maximum radiation
- All objects radiate thermally
- Darker surfaces beat shiny ones
Quick Check: A star is observed to emit blue light. What can you conclude about its temperature compared to a star emitting red light?
The blue star is hotter. Blue light has a shorter wavelength than red light. Since hotter objects emit peak radiation at shorter wavelengths, the blue star must have a higher surface temperature than the red star.
This memory aid covers Memory Aids within Black Body Radiation for GCSE Physics. Revise Black Body Radiation in Energy for GCSE Physics with 16 exam-style questions and 5 flashcards. This topic appears regularly enough that it should still be part of a steady revision cycle. It is section 6 of 10 in this topic. Use it for quick recall, then test yourself straight afterwards so the memory aid becomes usable in an answer.
Practice questions for Black Body Radiation
What is a perfect black body?
Explain how the radiation emitted by an object changes as its temperature increases.