Two parallel rays are travelling in a medium of refractive index `mu_(1)=4/3` . One of the rays passes through a parallel glass slab of thickness t and refractive index `mu_(2)=3/2` The path difference between the two rays due to the glass slab will be

Explanation

`Delta x=(mu_(2)/mu_(1) - 1)t = ((3//2)/(4//3))t = t/8`