![]() ![]() ![]() The resultant amplitude on screen at P 1 becomes Hence the intensity in a direction ‘v ‘ can be found by finding the resultant amplitude of N vibrations each of amplitude and a phase difference of ‘ ‘ The path difference between two consecutive slits is If there are N slits, then we have N diffracted waves. The wavelets proceeding from all points in a slit along their direction are equivalent to a single wave of amplitude starting from the middle point of the slit, Where The intensity at point P 1may be considered by applying the theory of Fraunhofer diffraction at a single slit. As a result dark and bright bands on both sides of central maximum are obtained. Now consider the secondary waves traveling in a direction inclined at an angle ‘ ‘ with the incident light will reach point P 1in different phases. Now, the secondary wavelets traveling in the direction of incident light will focus at a point P oon the screen. By Huygen’s principle, each of the slit sends secondary wavelets in all directions. Suppose a parallel beam of monochromatic light of wavelength ‘ ‘ be incident normally on the grating. Then (e+d) is known as grating element and XY is the screen. Let ‘e’ be the width of each slit and ‘d’ the width of each opaque space. A section of a plane transmission grating AB placed perpendicular to the plane of the paper is as shown in the figure Mathematical Expression: ![]() When the spacing between the lines is of the order of the wavelength of light, then an appreciable deviation of the light is produced. This is known as plane transmission grating. The ruled lines are opaque to light while the space between any two lines is transparent to light and acts as a slit. This is known as Gratings are constructed by ruling equidistant parallel lines on a transparent material such as glass, with a fine diamond point. Diffraction due to N-Slits (Grating):Īn arrangement consisting of large number of parallel slits of the same width and separated by equal opaque spaces is known as Diffraction grating.Gratings are constructed by ruling equidistant parallel lines on a transparent material such as glass, with a fine diamond point. It’s through this overlapping that the diffraction pattern of dark and bright areas is created. When light passes through each of the slits, it will spread out and overlap with the light from the other slit. Diffraction is when waves like light or sound spread out as they move around an object or through a slit. ![]()
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