Question

In thin-film interference, an interference pattern is formed...

A. due to the light polarizing as it reflects off the top and bottom layers of the film.
B.due to the light reflecting off the bottom layer of the film traveling a different number of wavelengths compared to the light reflecting off the top of the film.
C.due to the imperfections (such as dust or debris) contained within the thin film that absorbs some of the spectrum of the light in the film.

Answer 1

Interfrence in light reflected from a thin film is due to combination of rays reflected from the upper and lower surface of the film.It depends of the thickness of the film and refractive index and also on the angle of refraction.

The light rays which are reflected from top and bottom surface of the film superimpose each other and results in formation of colours by the phenomenon of interferece.

Hence correct statement is  A - due to the light polarizing as it reflects off the top and bottom layers of the film.