Question

Which color has the highest refractive index?

Answer 1

When white light is passed through a triangular prism of a material denser than air (say glass), dispersion occurs. We can observe that red is at the top and violet is at the bottom in this “spectrum”. So we can safely say that red is less deviated than violet.

So, red has the lowest refractive index among the colors in “VIBGYOR”.

Mathematically, we know that according to Snell’s law of refraction, the refractive index of any medium 1 with respect to another medium 2 is given by

n2n1=v1v2n2n1=v1v2

But v=λ.fv=λ.f, where vv is the wave velocity, ff is the frequency and λλ is the wavelength of the wave.

On refraction, wavelength and velocity change, whereas frequency does not. Hence,

n2n1=λ1λ2n2n1=λ1λ2

The colour of light or the wave having a higher wavelength will get refracted less. So, red with a higher wavelength gets refracted lesser than violet which has a comparatively higher wavelength.

Answer 2

we can safely say that red is less deviated than violet. So, red has the lowest refractive index among the colors in “VIBGYOR”. But. f , where is the wave velocity, is the frequency and is the wavelength of the wave.