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Q & A: radiation pressure

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Most recent answer: 05/24/2017
Q:
Thank you for taking the time. My question has to deal with the transfer of momentum of a photon. I know that when reflected, a photon exerts a forward momentum on the reflection plane. But what isn't explained is if the photon exerts a recoil on its source. In other words, does the light push away from its source with the same radiation pressure as when reflected? Thank you again. MO.
- Matt O. (age 29)
Chicago Illinois USA
A:

The light beam has some momentum, so the source did lose that momentum. There is a small recoil. The force from the light reflection is twice as big because the light momentum changes sign on reflection.

Mike W.


(published on 05/24/2017)

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