Final answer:
Wave rays or orthogonals represent the direction of wave propagation and are always perpendicular to the wave crests, which is crucial in understanding wave behavior and is a fundamental concept in wave optics.
Step-by-step explanation:
Wave rays, often referred to as orthogonals, are imaginary lines that represent the direction of wave propagation. When visualizing waves, particularly transverse waves such as light or electromagnetic waves, we often refer to the concepts of wave crests and wave rays. If we consider the overall view of a transverse wave, we can see the crests as the peaks of the waves, similar to the crests of ocean waves when viewed from above.
The orientation of wave rays with respect to the wave crests is crucial to understanding wave behavior. Wave rays are always perpendicular to the wave crests. This perpendicular relationship can be visualized by looking at a side view of a transverse wave, where we might see a graph of the electric or magnetic field of an electromagnetic wave, with the wave rays shown as arrows pointing in the direction of wave travel, orthogonal to the wave crests. This concept is an important part of wave optics and helps in understanding how waves move and interact with mediums and barriers.