Ray optics can be considered as a limiting case of wave optics because when the wavelength of light λ tends to zero, wave optics reduces to ray optics in the limiting case. In wave optics there is a diffraction region between the illuminated region and the shadow region whereas in ray optics the shadow is sharply separated by the illuminated region and no diffraction occurs at all. Ray optics deals with optical phenomenon without considering the wave nature of light.As geometrical diagrams known as ray diagrams are used in the study of this optics it is known as ray optics. When the size of the object is greater than the wavelength of the light, no diffraction or interference occurs. Therefore we can say that ray optics is a limiting case of wave optics.