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ludi_srbin
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I read about Cherenkov's effect and how light slows down if it goes through, let's say, water. My question is how it can speed up again after it exits the water?
I think technically the photons are obsorbed and 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.
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?
Light slows down when it enters a medium with a higher refractive index. This is because the photons of light interact with the particles in the medium, causing them to temporarily absorb and re-emit the photons. This process slows down the overall speed of light through the medium.
When light exits the medium, it returns to its original speed because the particles in the medium no longer interact with the photons. This allows the photons to travel at their original speed, resulting in an acceleration of the light.
No, the acceleration of light after being slowed down depends on the properties of the medium it is passing through. In some cases, the photons may continue to interact with the particles in the medium, resulting in a slower speed and no acceleration.
No, the acceleration of light after being slowed down is a result of the conservation of energy and momentum. When light is slowed down, the energy and momentum of the photons are transferred to the particles in the medium. When the light accelerates, the energy and momentum are transferred back to the photons, maintaining the overall conservation of these quantities.
No, the speed of light is a fundamental constant and can never be exceeded. While it may appear that light is accelerating after being slowed down, it is simply returning to its original speed and not exceeding it.