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 λ. 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.

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. Does this mean that the wavelength of visible light gives little indication on its colour? Is frequency the sole deciding factor then?