ABSTRACT
In our daily lives, we are accustomed to the formation of a shadow when an object is illuminated with light. From a broad perspective, our experience with the shadow of an object confirms our basic understanding of light as having rectilinear propagation. A closer inspection of the boundary between the illuminated and the shadow region reveals that the transition from one to another is never abrupt. A more detailed investigation reveals the oscillatory nature (in space) of the light-shadow boundary, which is a consequence of the wave nature of the light giving rise to diffraction, studied in Chapter 7. In our daily lives, we are mostly concerned about the visual appeal of objects much larger than the wavelength of light used to probe them. We thus consider a regime of optics to explain our daily experiences with objects around us and some devices we often use (telescopes, binoculars, camera, etc.). In reality many of these devices were developed long before a satisfactory understanding of wave and physical optics.
