The key to understanding diffraction is a very simple observation first due to huygens in 1678. Diffraction is the bending of light around obstacles or openings, particularly when the size is comparable to the wavelength of light. The phenomenon of bending of light waves around edges of small obstacles and hence it's spreading into the geometrical shadow of the obstacle is called diffraction The diffraction effects were first observed by grimaldi in 1665. We will be recording the various orders and angles of diffraction for the various spectral lines (distinct colors) produced by the lamp, and we will use these along with the appropriate dfor the diffraction grating to calculate the wavelengths of these spectral lines. The diffraction is thus produced by the interference between parallel rays.
One focus of physics in the study of light is to understand and put to use the diffraction of light as it passes through a narrow slit or (as we shall discuss) past either a narr W obstacle or an edge A more complete description of diffraction and interference phenomena can be found in textbooks such as in chapters 21 and 22 of physics for scientists and engineers by knight, or chapter 29 of bauer & westfall. The phenomenon of binding of light waves around the obstacle and entering into the region of the geometrical shadow of the obstacle, is called diffraction of light. Pdf | the main theories of diffraction are briefly described and their more important results compared. This chapter discusses the phenomenon of diffraction of light
