Answer to Question #250915 in Physics for emmanuel

Question

a thin hair of water of refractive index 1.33 and constant thickness is trapped between two glass plates (n = 1.33). white light normally falls on the water film. When viewed perpendicular to the water film, the film regulates light of wavelength 400 more strongly and does not reflect light of wavelength 500 nm. the thickness of the water film in nanometers is

Answer 1

$$t_m=\frac{500}{2\cdot1.33}=188\ nm$$