As the angle of incidence increases for a ray incident on a reflecting surface, the angle between the incident and reflected rays will ultimately approach a value of 90 degrees. This is a fundamental property of reflection known as the Law of Reflection, which states that the angle of incidence is equal to the angle of reflection.
The angle between the incident and reflected rays is also small, but as the angle of incidence increases, the angle between the two rays becomes larger. When the angle of incidence reaches 90 degrees, the reflected ray will essentially "bounce off" the surface at a right angle to the surface, resulting in the angle between the incident and reflected rays being 90 degrees. So, the reflected ray will be parallel to the reflecting surface, and any further increase in the angle of incidence will result in the reflected ray essentially "reflecting back" into the surface in the opposite direction. This is why the angle between the incident and reflected rays approaches a value of 90 degrees as the angle of incidence increases.
