Harald
Thanks again. Interestingly the link you provided is one my son referred to when we discussed the same question. So now I know where he got it from.
Harald, thanks for the clarification. I'm not clear on the distinction between absorption and re-emission by the lattice, and causing a variation in vibration leading to the emission of a new wave. However the key point remains that, as in my previous post, light itself does not slow down, it...
Thanks to both for your responses, and thanks also for not telling me off for not finding that post myself:redface:
So that does pretty much answer my first question. Light itself does not slow down, it just gets "interfered with" on its way through the medium. Hence there is no...
As you will see this is my first post so I apologize if I have chosen the wrong sub-forum. My academic training (maths) was many years ago and it now seems to me that for the last 30 or so years my brain has been in a kind of intellectual limbo from which it is only now beginning to emerge, so...