Question

A transparent oil with index of refraction 1.15 spills on the surface of water (index of refraction 1.33), producing a maximum of reflection with normally incident violet light (wavelength 400 nm in air). Assuming the maximum occurs in the first order, determine the thickness of the oil slick.

Answer 1

Answer:

The thickness of the oil slick. t = 173.91 nm

Explanation:

Oil film thickness t is given by the equation

$t = \frac{\lambda}{2n}$

where λ = wavelength of incident light in air = 400 nm

and n = index of refraction of oil

therefore,

$t =\frac{400}{2\times 1.15}\\t= 173.91 nm$

The thickness of the oil slick. t = 173.91 nm