Practice question · Put in order
Arrange these wavelengths of light from lowest photon energy to highest.
- Red light, 700 nm
- Ultraviolet, 200 nm
- Radio, 1 m
- Infrared, 1000 nm
- Blue light, 450 nm
Hints
- Photon energy rises as wavelength falls.
- The longest wavelength carries the least energy per photon.
Show the answer
- Radio, 1 m
- Infrared, 1000 nm
- Red light, 700 nm
- Blue light, 450 nm
- Ultraviolet, 200 nm
Why
Since , energy is inversely proportional to wavelength: the metre-scale radio photon is weakest and the 200 nm ultraviolet photon strongest.
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