Reflection Of Light By Spherical Mirrors

Two plane mirrors A and B are aligned parallel to each other, as shown in the figure. A light ray is incident at an angle at a point just inside one end of A. The plane of incidence coincides with the plane of the figure. The maximum number of times the ray undergoes reflections (including the first one) before it emerges out is

A wave has velocity in medium and velocity in medium . If the wave is incident in medium at an angle then the angle of refraction will be