Question

A transparent oil with index of refraction 1.28 spills on the surface of water (index of refraction 1.33), producing a maximum of reflection with normally incident orange light (wavelength 600 nm in air). Assuming the maximum occurs in the first order, determine the thickness of the oil slick. nm

Answer 1

To solve this problem we will apply the concepts related to the principle of destructive and constructive interference. Mathematically this expression can be given as

$2nt = m\lambda$

Here,

n = Index of refraction

t = Thickness

m = Order of the reflection

$\lambda$ = Wavelength

We have all of this values, therefore replacing,

$2(1.28)t = (1)(600nm)$

$t = 233nm$    

Therefore the thickness of the oil slick is 233nm