Answer:
94 nm
Explanation:
We are given that
Wavelength of light,[tex]\lambda=500 nm=500\times 10^{-9} m[/tex]
[tex]1 nm=10^{-9} m[/tex]
n=1.33
We have to find the minimum thickness of film that will give an interference maximum when the light is incident normally on it.
We know that minimum thickness of film,d=[tex]\frac{\lambda}{4n}[/tex]
By using the formula
[tex]d=\frac{500\times 10^{-9}}{4\times 1.33}[/tex]
d=[tex]9.4\times 10^{-8}=94\times 10^{-9} m[/tex]
d=94 nm
