Consider. a parallel beam of light from a lens falling on a slit AB. As. diffraction occurs, the pattern is focused on the screen XY with the. help of lens L2. Each point on the unblocked portion of. plane wavefront AB sends out secondary wavelets in all directions. The. waves from points equidistant from the center C lying on the upper as we will as. lower half reach the point O with path difference being zero as we will as hence. reinforce each other producing a maximum intensity at the point 0. . The waves are travelling from more dense to a less dense medium. These aren’t stopped till these are reached at the end of the medium. The term reflection, diffraction as we will as refraction are very similar to each other. Reflection is the process that includes the alteration in direction of waves when the wave is bounced off from the edge of the barrier while refraction of waves involves a change in the direction of waves when the wave is travelling from one medium to another medium The diffraction. is the process of change in the direction of waves when a wave is passed around a barrier in its travelled path. Diffraction can be detected by using small barriers in the path of water waves in a ripple tank. Here we are discussing about the process of diffraction, its different types with its single slit experiment. The amount of diffraction shows bends sharpness which depends on the wavelength. It increases with increasing wavelength. Let’s discuss the diffraction in detail .