Physics - Geometrical Optics Question with Solution | TestHub

Optical path length is given by the product of the refractive index and the geometric thickness of the medium.

For the first medium, the optical path length is $x_1=n_{1}d$.

For the second medium, the optical path length is $x_2=n_2\left(\frac{d}{4}\right)$.

The total optical path length is the sum of the individual optical path lengths:

$x=x_1+x_2$

$x=n_{1}d+\frac{n_{2}d}{4}$

$x=\frac{d(4n_1+n_2)}{4}$

Answer: $\frac{d(4n_1+n_2)}{4}$