Physics › Section U · Quantum and atomic physics › Topic U.2
Photon energy and momentum
Why can ultraviolet light burn your skin while far more intense infrared only warms it? The answer lies in the energy of each photon. Photons also carry momentum, enough to push a comet's dust tail away from the Sun and to steer a spacecraft on sunlight alone.
In this topic
- Every photon has its own energy
- Photon energies across the spectrum
- Why photon energy decides the effect
- Worked example: photons from a laser pointer
- Worked example: germicidal ultraviolet
- Photons carry momentum
- The Compton effect
- Light pressure and solar sails
- Worked example: a solar sail
- Common mistakes to avoid
- Key takeaways
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