Question

Explain the relation between refractive index and wavelength of light.

Answer 1

The refractive index is the ratio of the velocity of light through the vacuum to the velocity of light through the medium.  

$n=\frac cv$

The refractive index is related to the wavelength by substituting the velocity formula.

velocity=frequency×wavelength=fλ

$n=\frac{f\lambda_\o}{f\lambda}=\frac{\lambda_\o}{\lambda}$

The wavelength of the light changes according to the density of the medium and frequency remains same irrespective of the medium.  

So, the refractive index of light depends only on the wavelength, not on the frequency. So the light with higher wavelength disperses more than light with lower wavelength. This effect is called optical dispersion.

Answer 2

Answer:

The refractive index is the ratio of the velocity of light through the vacuum to the velocity of light through the medium.

n=\frac cvn=

v

c

The refractive index is related to the wavelength by substituting the velocity formula.

velocity=frequency×wavelength=fλ

n=\frac{f\lambda_\o}{f\lambda}=\frac{\lambda_\o}{\lambda}n=

fλ

fλ

\o

=

λ

λ

\o

The wavelength of the light changes according to the density of the medium and frequency remains same irrespective of the medium.

So, the refractive index of light depends only on the wavelength, not on the frequency. So the light with higher wavelength disperses more than light with lower wavelength. This effect is called optical dispersion.