Difference between Interference and Diffraction
Interference |
Diffraction |
Interference is produced by superposition of waves from two coherent sources. | Diffraction is produced by superposition of waves originating from different parts of the same wavefront. |
The width of the central bright band is the same as that of any bright band. | The central bright band is much broader than other bright bands. |
Both dark and bright bands are equally spaced. | Dark bands on either side of the central bright band are equally spaced. |
Two coherent sources of equal intensity give rise to a pattern in which there is a sharp contrast between bright and dark bands. | In a diffraction pattern the contrast between bright and dark bands is always poor. |
Intensity of all bright bands is same. | The intensity of central bright band is maximum. The intensity goes on decreasing with the order of bright bands on both the sides. |
Problems on Diffraction – Class 12 Physics
The bending of light at the edges of an obstacle whose size is comparable to the wavelength of light is called diffraction. To put it another way, it is the spreading of waves when they go through or around a barrier. Diffraction of light, as it is used to describe light, occurs more explicitly when a light wave passes by a corner or via an opening or slit that is physically smaller than the wavelength of that light, if not even smaller. The ratio of the wavelength of the light to the opening size determines how much bending occurs. The bending will essentially be undetectable if the aperture is substantially greater than the light’s wavelength. However, if the two are of similar size or are equal in size, there is a noticeable degree of bending that can be observed with the unaided eye.