Answer:
the third non zero thickness is t = 586.466 nm
Explanation:
For a constructive interference, the non zero thickness is given by the formula:
[tex]t = \frac{m \lambda}{2n}[/tex]
Where n = 1.33
m = 3
[tex]\lambda = 520 nm = 520 * 10^{-9} m[/tex]
[tex]t = \frac{3 * 520 * 10^{-9} }{2*1.33}[/tex]
t = 586.466 * 10⁻⁹ m
the third non zero thickness is t = 586.466 nm