Question

A light ray is partially reflected and partially refracted at a boundary between two media, the upper one having index of refraction n, the lower one having index of refraction n', as shown in the figure. The reflected ray is perpendicular to the refracted ray when?

Answer 1

The reflected ray is perpendicular to the refracted ray at the Brewster's angle, where the angle of incidence and the indices of refraction satisfy a specific relationship.

Step-by-step explanation:

The conditions under which a reflected ray is perpendicular to the refracted ray when a light ray crosses a boundary between two media can be understood by examining the properties of refraction and reflection. When a light ray moves from a medium with a higher index of refraction to a lower one, the refracted ray bends away from the normal, and the reflected ray remains at the same angle to the normal but on the opposite side of the incident ray.

The reflected ray will be perpendicular to the refracted ray at the specific condition known as the Brewster's angle, where the sum of the angles of the reflected and refracted rays equals 90 degrees. This occurs when the tangent of the angle of incidence is equal to the ratio of the indices of refraction of the two media.