A glass slab is made such that the refractive index of the material increases with its depth. The glass slab is kept in air and a light ray is incident on its top face. How will the light ray pass through it ?

Explanation

As the slab is kept in air, the light beam is moving from a rarer medium to denser medium, thus it will bend towards the normal. But, as the refractive index of the slab is increasing with depth, the light beam will experience similar refraction at a number of points and traces a curved path as shown in the adjoining figure.