Fugie Runner
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Do photons reflected off prisms exert directional force however small as they are reflected off the hypotenuse side of a right triangle shaped prism?
Reflection of Photons on Prisms: Directional Force?
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Light carries momentum, which is a vector quantity, that is, it has both magnitude and direction. Therefore, if a beam of light changes direction, something must recoil in order for the total momentum to be conserved. This is true in both the classical and quantum models of light.
humanino
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I fully agree with jtbell answers. I would like to point out that the original question suggests that photons can somehow bounce off a surface. Technically however, photons being massless cannot be put at rest, so must be absorbed and re-emitted. Maybe just nitpicking 
jimgraber
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humanino said:I fully agree with jtbell answers. I would like to point out that the original question suggests that photons can somehow bounce off a surface. Technically however, photons being massless cannot be put at rest, so must be absorbed and re-emitted. Maybe just nitpicking
Wow, I never thought a reflection or an elastic scatter involved a state of rest. However, I can accept that absorption and re-emission is mathematically equivalent to a reflection or a scatter. Is this really the way it is treated in QM or QFT? Also, is the momentum of the reflection absorbed by a single atom, or by the entire prism or mirror, similar to the Mossbauer effect?
Inquiring minds want to know. TIA.
Jim Graber