# Does light color change when refracting? [duplicate]

When light refracts from a medium to a second one, its frequency stays the same, and its wavelength changes. If this is true, why we see the refracted light ray's colour is the same as the incident light ray in the second medium? The colors should not be the same. If the wavelength changes, colour should change too.

• When seeing, isn't the last medium the light passes through always the stuff in your eyeballs? – Řídící Mar 17 '14 at 20:15
• Frequency does not change moving through another medium, so a (better?) different question to ask is whether color is dependent on wavelength or frequency. – NeutronStar Mar 18 '14 at 5:26

The color will not change. What you're not taking into account is the speed of light in the medium. It's not the same $c$ en vacuo. The frequency stays the same. What changes is that speed of light in the refracting medium and as a result wavelength. This difference for speed is the exact reason we have refractive effects, and I believe was the observation that led to Snell's Law. In symbols $$\lambda = \frac {c} {\nu}$$ where $\lambda$ is the wavelength and $\nu$ is the frequency.