Ray optics fails when

Ray optics is valid,when characteristic dimenstions are

Ray optics is valid when characteristic dimensions are

Ray optics is valid when characteristic dimensions are

Ray optics is based on:

Ray optics is based on the assumption that light travels in a straight line. Diffractions observed when light propagates through small apertures/slits or around small objects disproves this assumption. Yet the ray optics assumption is so commonly used in understanding location and several other properties of images in optical instruments. What is the justification?

Ray optics is based on the assumption that light travels in a straight line. Diffraction effects (observed when light propagates through small apertures/slits or around small obstacles) disprove this assumption. Yet the ray optics assumption is so commonly used in understanding location and several other properties of images in optical instruments. What is the justification?

Ray optics is valid, when characteristic dimensions are