A thin layer of oil (n = 1.25)is on top of a puddle of water (n = 1.33).If normally incident 500-nm light is strongly reflected,what is the minimum nonzero thickness of the oil layer?
A) 200 nm
B) 250 nm
C) 100 nm
D) 400 nm
E) 150 nm

Question

Quizplus · Accepted Answer

The condition for strong reflection from a thin film is 2nt = mλ, where m is an integer. For m = 1 and λ = 500 nm, we have 2nt = 500 nm, so t = 250 nm.

A Thin Layer of Oil (N = 1