Question

Find the thickness of water film with
refractive index of 1.33 formed on a
glass window - pane to act as non-
reflecting film. Given \= 5500 Å *
O a)1033 Å
O b)5033 Å
O c)8094 Å
O d)2894 Å​

Answer 1

Given:

μ = 1.33

λ = 5500 Å

To find:

t =?

Explanation:

The wavelength of ray for the non-reflecting film is given as

2μt = ( n - 0.5) λ       ... n = 1, 2, 3 ...

where

λ = wavelength of the ray

μ = the refractive index of the film

t = thickness of the film

n = no of the films

Here n =1 & putting given values, the above equation becomes

2 × 1.33 × t = ( 1 - 0.5 ) 5500

2.66 t = 0.5 × 5500

∴ t = 1033 Å

The thickness of water film is 1033 Å