What is the thinnest soap film (excluding the case of zero thickness) that appears black when illuminated with light with a wavelength of 565 nm ? The index of refraction of the film is 1.33, and there is air on both sides of the film.

answer: the correct answer for the fill in the blank is rods.

rods are the specialized photoreceptor cells that are present in the retina of human eye. they are responsible for vision in the night time ( also called scotopic vision). they have very low visual acuity and color distinguishing ability.

as they are responsible for vision in night time, therefore they are found predominantly in the nocturnal animals.