The Table shows the temperature of four objects and the wavelength at which each object emits radiation with the greatest intensity (the peak wavelength).
Visible light has wavelengths from 0.40 μm0.40\ \mu\text{m}0.40 μm to 0.70 μm0.70\ \mu\text{m}0.70 μm.
Table
| Object | Temperature in ∘C^{\circ}\text{C}∘C | Peak wavelength in μm\mu\text{m}μm |
|---|---|---|
| human skin | 33 | 9.5 |
| electric heater element | 700 | 3.0 |
| filament lamp | 2500 | 1.0 |
| surface of the Sun | 5500 | 0.50 |
Describe the relationship between temperature and peak wavelength shown in the Table.
Use the data to explain why a filament lamp is an inefficient source of light.
A student says:
'The human body does not emit any radiation because it is too cold to glow.'
Explain why the student is wrong.
The temperature of the filament is increased to 3000 ∘C3000\ ^{\circ}\text{C}3000 ∘C.
Predict how the peak wavelength changes.
Explain how this affects the proportion of the energy emitted as visible light.
96 exam-style questions on Edexcel GCSE Physics 5.3 Black body radiation, covering 5.3.1 Emission of radiation and temperature, 5.3.2 Radiation balance and constant temperature, and 5.3.3 The temperature of the Earth. Each one has a worked solution and a mark scheme showing where the marks go.