Hi there! Sorry if this is dumb question, but i learnt in school the other day that when light enters a medium with a higher refractive index it refracts. Since light is an EM wave, it can be expressed in the following equation: v = f ?. It will most definitely slow down, meaning that its velocity will decrease. However, since its frequency will not change, its wavelength will have to compensate the decrease in velocity by decreasing in magnitude itself. However, it is well known that the refracted light will not change colour.
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agreed!

For example, if the laser used was red, the refracted red beam would have a smaller wavelength that might fall within yellow's band of wavelengths. But the refracted beam will always remain as red, apparently.
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i agree with prof hwang that the light you mentioned has to exit the medium and enter air again thus it will appear to be red light again when it enter our eyes.

Does this mean that the wavelength of visible light gives little indication on its colour?
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i disagree here with Puzzled
wavelength of visible light is indeed ~400 to 700 nm as mention in http://en.wikipedia.org/wiki/Visible_spectrum [img]http://upload.wikimedia.org/wikipedia/commons/thumb/d/d9/Linear_visible_spectrum.svg/200px-Linear_visible_spectrum.svg.png[/img]