Question

A composite slab consisting of different media is placed in front of concave mirror of radius of curvature $150cm$ as shown in Fig. The whole arrangement is immersed in water. Locate the final image of point object $O$.

Answer 1

The image formed after $4$ refractions would be taken as the object. The distance of object ($4^{th}image)$ from mirror's pole is given by
$x=(\frac{20}{4/3}+\frac{54}{1.5}+\frac{24}{1.0}+\frac{45}{1.5})\times \frac{4}{3}+10$
$=150cm$
i.e., the center of curvature of mirror. Hence, the ray will retrace its path, i.e., it is formed on the object itself.