I read about Cherenkov's effect and how light slows down if it goes through, lets say, water. My question is how it can speed up again after it exits the water?
This is correct.I think technically the photons are obsorbed and re-emitted,
Absorption and re-emission is a good way of to explaining it. Individual photons always travel at 'c', but they occasionally gets absorbed, held for a while, then re-emitted.εllipse said:I'm not sure of the technicalities.
A photon never bounces! It is adsorbed by the atomic structure then reemitted a short time later. The direction taken by the reemitted photon will be determined by QM and material properties.Myriad209 said:Umm, photons simply bounce off molecules. That's why you actually see light in the first place without actually looking directly at the source. If you took a flashlight and turned it on in space, you wouldn't see the light beam unless your pointed it right at your eye.
It seems as if I've tried to explain this a gazillion times already... :)ludi_srbin said:Is that absorbtion responsible for the slow down, and how does it speed up again?
The absorption is responsible for the appearance of the slow down and it appears to speed up again as soon as it leaves the substance. But a physical photon (oversimplification) only ever travels at C.ludi_srbin said:Is that absorbtion responsible for the slow down, and how does it speed up again?