Revered members, What is the difference between wave and wave front? Geometrically both are represented in the same way. Take for example, my attachment, Here AB is the incident wave front and the perpendiculars drawn to AB at the points A and B that is PA and QC are incident rays. Do perpendiculars drawn to the top and bottom of the incident wave front qualifies as incident rays? Similarly in my second attachment PA and QBC are incident rays, while AB is incident wave front.