Question

Write the charcteristic property of which never changes when light travels in different media?

Answer 1

It is the frequency of the light that doesn't change. This I can justify with the help of Planck's formula, E=hf, where ‘E’ is the Energy of one light quantum (one photon), ‘h’ is the Planck's constant and ‘f ’ is the frequency. Because a photon can't be split into pieces, its energy stays constant and so does the frequency of the beam. Frequency of light does not ever change, as long as you can be sure that the photons are the same as the photons at the beginning. Putting mathematically, since speed of light and its wavelength are not absolute quantities and vary from medium to medium, their ratio changes in such a way that the frequency stays constant