Difference Between Diffraction and Interference
There are following differences between Diffraction and Interference are discussed in the table below,
Characterization |
Diffraction |
Interference |
|---|---|---|
| Definition |
The phenomena which bend the light around the apertures or obstacles of size comparable to the wavelength of light and spread it into the different regions of the aperture. |
The phenomena which superpose two waves traveling in the same direction in the same medium to form different wavefronts. |
| Result |
Superposition of secondary waves from different coherent sources on the same wavefront. |
Superposition of two waves in which the sum of the intensities of two waves is different from the resultant intensity of the wave. |
| Fringe Intensity |
Variable fringe intensity i.e. the intensity of fringe decreases on moving away from the central fringe on both sides |
Constant fringe intensity i.e. there is no change in the intensity of bright fringes on moving away from the central spot on either side of the fringe. |
| Fringe Width |
Unequal fringe width i.e. the width of the central maximum is twice the secondary maximum |
Equal fringe width whether bright or dark |
| Requirement of Slit |
Slits are required for diffraction. |
No slits are required for interference. |
| Difference Between Maxima and Minima |
The darker fringes are not perfectly dark hence there is poor contrast between bright and dark fringes. |
There is greater contrast between the bright and dark fringes i.e. regions of dark fringes are perfectly dark. |
| Position of Dark and Bright Fringe |
We get the first dark fringe at an angle of λ/a where a is the width of the slit. |
We get the first bright fringe at λ/d where d is the distance between two slits. |
| Direction of Wave | Waves after diffraction change the direction of their propagation | There is no change in the direction of propagation of the wave in the case of the interference |
Difference Between Diffraction And Interference
Diffraction and Interference are two important phenomena studied in Wave Optics. These phenomena are linked to the Wave Nature of the matter. We know that when photons are emitted from the source they start oscillating in space and the locus of all such oscillating particles in the same phase is called Wavefronts. As per Huygens Wave Theory, each point on the Wavefront acts as a source of secondary Wavelets which later add up to give a new Wavefront. The sources of these Wavefronts can be coherent or non-coherent depending upon whether the phase difference is constant or not. These wavefronts interact with each other and with other particles to give rise to the phenomena of Interference and Diffraction respectively.
In this article, we will learn about what is diffraction, what is interference and what are the differences between Diffraction and Interference.