Question

What is the wavelength of object inside inside a material if the material has an index of refraction `n = 38.6` and frequency `0.32` THz?

Answer 1

Refractive index of a media(`n`) = velocity of light in vaccum(`c`)/velocity of light in that media(`v`)

So, `n=c/v`

given, `n =38.6` and we know `c=3*10^8 ms^-1`

So, `v = c/n =0.08*10^8 ms^-1`

Now, wavelength (`lambda`) , frequency(`nu`) and velocity (`v`) of a wave are related as follows,

`v=nulambda`

Given, `nu = 0.32*10^12 Hz`

So, `lambda = v/nu=0.25*10^-4=2.5*10^-5 m`