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Old 19-05-2011, 09:45 AM
Keshdogga (Casey)
Casey Roff

Keshdogga is offline
 
Join Date: Oct 2010
Location: Brisbane, QLD, Australia
Posts: 91
Quote:
Originally Posted by renormalised View Post
The light doesn't act as a particle, it acts as a wave. The velocity of the light does, in reality, decrease as it enters the denser medium. It's not an apparent decrease. The direction of travel changes because the wave changes its velocity upon entering the denser medium. Those parts of the wave still outside the medium remain at their original velocity until they enter the medium. You answered your question in the bold analogy, above. You have to get used to thinking along the lines of the particle-wave duality. A photon is both simultaneously and it's acting as a wave when it enters the interface between the two media.

Light also scatters and does act as particles as well

You have two types of scattering/reflection, Specular and Lambertian. Specular scattering/reflection occurs when light strikes a surface and then scatters (reflects) back at the same angle it strikes that surface, much like a mirror. Lambertian scattering (reflection) is where the incident light strikes a surface and scatters equally in all directions, no matter the angle of incidence. Calm water is a specular scattering surface and the reason why it acts like a mirror when you look into it. An example of a Lambertian scattering surface would be sandpaper....basically any rough textured surface will scatter light in all directions, no matter the incident angle of the incoming rays (this being within reason...a mountain range is not a Lambertian reflection surface!!!).
Thanks for you're responce Carl but unfortunately i can't get much more out of what you're saying other than light slows down when it hits a denser mdeium because it does. I'm still boggled as to how density can cause the wavelength of light to change? Doesn't the wavelength of a photon only change its energy? Am I being ignorant of some fundamental properties of light?
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