Answer:
The right solution is "165.8 nm".
Explanation:
Given:
Index of refraction,
n = 1.81
Wavelength,
λ = 600 nm
We know that,
⇒ [tex]t=\frac{\lambda}{2\times n}[/tex]
By putting the values, we get
[tex]=\frac{600}{2\times 1.81}[/tex]
[tex]=165.8 \ nm[/tex]