$example of diffraction of a wave$

$example of diffraction of a wave$

When these reach the wavefront AC, ray 5 would have a path difference ab say equal to λ/2.

$example of diffraction of a wave$

Let us consider rays 1 and 5 which are in phase on in the wavefront AB. In this figure, only nine rays have been drawn whereas actually there are a large number of them. It becomes simple to deal with rays instead of wavefronts as shown in the figure. These wavelets then interfere to produce the diffraction pattern. Each point of this section of the wavefront sends out secondary wavelets to the screen. A small portion of the incident wavefront passes through the narrow slit. The screen S is placed parallel to the slit for observing the effects of the diffraction of light. The slit AB of width d is illuminated by a parallel beam of monochromatic light of wavelength λ. The figure shows the experimental arrangement for studying diffraction of light due to the narrow slit. See Also : Interference of light Diffraction due to Narrow slit The diffraction of light occurs, in effect, due to the interference between rays coming from different parts of the same wavefront. The phenomenon is found to be prominent when the wavelength of light is compared with the size of the obstacle or aperture of the slit. These two experiments clearly show that when light travels past an obstacle, it does not proceed exactly along a straight path, but bends around the obstacle. According to Huygens’s principle, each point on the rim of the sphere behaves as a source of secondary wavelets which illuminate the central region of the shadow. The shadow of the spherical object is not completely dark but has a bright spot at its centre. Another simple experiment can be performed by exhibiting the same effect.Ĭonsider that a small and smooth ball of about 3 mm in diameter is illuminated by a point source of light.The shadow of the object is received on a screen as shown in the figure. If light travels in a straight path, the central region should appear dark i.e., the shadow of the screen between the two slits. In Young’s double-slit experiment for the interference of light, the central region of the fringe system is bright.

$example of diffraction of a wave$

See Also: Refraction of light Diffraction of light The convex lens is not needed to converge the spherical wavefronts.Wavefronts leaving the obstacles are also spherical.Source and screen are not far away from each other.

$example of diffraction of a wave$

Example of diffraction of a wave