Reflecting Photon Velocity
Most recent answer: 02/18/2015
- Annette (age 55)
Toronto, Canada
Hi Annette-
I think the old answer you have in mind is follow-up 18 on
Certainly if you say it's the same photon it's correct to say that the velocity has changed but the speed hasn't.
Yes, you can think of the velocity of each "piece" of the photon wave as changing discontinuously, but since there's a smooth continuum of "pieces" the overall change is still continuous. That's one way to avoid having any part ever have zero velocity. The intermediate value theorem only applies to continuous functions, as you remembered from those old courses.
I guess if we were to get very careful then in addition to the wave coming in at c and the one leaving at c (both of which we're calling part of the same photon) there's some wave in the reflecting material, coupled with excitations of the electrons there. Offhand, I'm not sure how to describe that part in terms of local velocities.
Mike W.
(published on 02/18/2015)