Physics - Geometrical Optics Question with Solution | TestHub

A glass slab consists of thin uniform layers of progressively decreasing refractive indices RI (see figure) such that the RI of any layer is $\mu -m\Delta \mu$. Here, $\mu$ and $\Delta \mu$ denote the $\mathrm{RI}$ of 0 th layer and the difference in RI between any two consecutive layers, respectively. The integer $m=0,1,2,3,\dots$ denotes the numbers of the successive layers. A ray of light from the oth layer enters the 1st layer at an angle of incidence of $30^{\circ }$. After undergoing the mth refraction, the ray emerges parallel to the interface. If $\mu =1.5$ and $\Delta \mu =0.015,$ the value of $m$ is