Answer:
The value is [tex]t = 1.374 *10^{-7} \ m[/tex]
Explanation:
From the question we are told that
The refractive index is [tex]\mu = 1.29[/tex]
The wavelength is [tex]\lambda = 709 \ nm = 709 *10^{-9} \ m[/tex]
Generally the condition for constructive interference is
[tex]2 * \mu * t = (n - \frac{1}{2} )\lambda[/tex]
At minimum thickness(t) the order of the fringe(n) will be equal to 1
So
[tex]2 * 1.29 * t = (1 - \frac{1}{2} )* 709 *10^{-9}[/tex]
=> [tex]t = 1.374 *10^{-7} \ m[/tex]
