A designer tested two prototype metal casings for a high-power lamp. The casings were identical except that one had a matt black outer surface and the other had a shiny silver outer surface. The results were labelled P and Q without identifying the surface used on each casing.
The designer maintained each casing at several temperatures and measured the intensity of the infrared radiation it emitted.
| Temperature in ∘C^\circ\text{C}∘C | Intensity emitted by casing P in W m−2\text{W m}^{-2}W m−2 | Intensity emitted by casing Q in W m−2\text{W m}^{-2}W m−2 |
|---|---|---|
| 40 | 520 | 45 |
| 60 | 660 | 56 |
| 80 | 835 | 70 |
Calculate the energy emitted as infrared radiation by each square metre of casing P during 5 minutes at 60 ∘C60\ ^\circ\text{C}60 ∘C.
The casings are then heated from 80 ∘C80\ ^\circ\text{C}80 ∘C to 100 ∘C100\ ^\circ\text{C}100 ∘C. Explain which finish was used on each casing and how this increase in temperature affects both the intensity and the peak wavelength of the radiation emitted by each casing.
106 exam-style questions on AQA GCSE Physics 6.3 Black body radiation, covering 6.3.1 Emission and absorption of infrared radiation and 6.3.2 Perfect black bodies and radiation. Each one has a worked solution and a mark scheme showing where the marks go.