Calculate the energy in eV corresponding to the 545 nm of light inside a medium with refractive index 2

Answer 1

The energy of a photon is given as E = h c / λ . where h is the Planck's constant, c is the speed of light and λ is the wavelength of the photon in the medium. The wavelength of the photon depends on the refractive index of the medium as

λ = λ_o / n where λ₀ is the wavelength of the photon in vacuum (n=1). So, in this problem the wavelength of the photon can be found as

λ = 545 nm / 2 = 272.5 nm

As a very useful relation, the product of h and c is given as hc= 1241.5 eV nm . Then, for the energy we have,

E = 1241.5 (eV) (nm) / 272.5 (nm) ≈ 4.56 eV