Answer:
The correct option is H
Explanation:
From the question we are told that
The index of refraction of coating is [tex]n_1[/tex]
The index of refraction of material is [tex]n_2[/tex]
Generally the condition for constructive for a thin film interference is mathematically represented
[tex]2 * t = [ m + \frac{1}{2}] \frac{\lambda}{n_1 }[/tex]
Here t represents the thickness
For minimum thickness m = 0
So
[tex]2 * t =0 + \frac{1}{2}\frac{\lambda}{n_1 }[/tex]
=> [tex]t =\frac{\lambda}{4n_1 }[/tex]
