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The law of diffraction is quite helpful in manufacturing and designing modern technological appliances or instruments that can help researchers to determine the characteristics of a particular material. There are crystals available in our nature and the molecular construction of the crystals can vary as well. There are simple crystals that diffract X-rays due to the atomic positions as in the case of simple crystals, the planes of atoms are equally spaced. It has been proven by Bragg’s law.
Researchers have invented a particular kind of instrument that is named a diffractometer that is based on the concept of diffraction. This particular instrument can produce diffraction patterns with the help of X-ray diffraction and it is used to compare different kinds of crystals in order to determine and find out the different molecular structures of different types of crystals.
The concept of interference is widely used in different kinds of optical testing. This concept is particularly used to test the surface quality. Some practical applications of this concept can also be mentioned here. The concept of interference is used when it comes to retrieving images from devices like telescopes and measuring the intensity of lights.
When a train passes through the tunnel, the headlight of the engine spreads around and we see darkness all around, do you know why this happens? This happens because of diffraction.
Diffraction is the spreading of light in the dark areas when it passes through a narrow lane or an area and this is accompanied by interference between the waveforms produced. So, what interference is? Interference is the combination of two or more electromagnetic waveforms that form a resultant wave in which the displacement is either reinforced or canceled.
Interference
Interference is the phenomenon that takes place when the meeting of the two waves takes place as they travel along with the same medium. Besides this, the interference causes the medium to take a particular shape or orientation. Moreover, this shape is due to the whole or the net effect of two individual waves on the medium’s particles.
Diffraction
Diffraction happens due to the spreading out of waves passing through an aperture. In the case of diffraction, the size of the obstacle or aperture is of similar straight dimensions to the incident wave’s wavelength, and its occurrence is significant. Furthermore, it takes place when the traveling wavelength’s part gets obscured or shaded.
Distinguish Between Interference and Diffraction
Now, let us find the difference between interference and diffraction in tabular form:
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Interference |
Diffraction |
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Interference happens because of the superposition or overlapping of two waveforms coming from two different coherent sources. |
Diffraction happens because of the superposition of secondary wavelets from the different parts of the wavefront. |
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The fringe width in interference is generally constant. |
Fringes are of varying width in diffraction. |
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We also find that bright fringes are of the same intensity. |
Intensity falls quickly. It means that in a diffraction pattern, the intensity of successive fringes goes on decreasing. |
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It means in an interference pattern, the number of bright fringes have the same magnitude of intensity. |
This means that diffraction fringes are wide near the obstacle and their width goes on decreasing while approaching the shadow side. |
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All the maxima in interference have the same magnitude of intensity. |
The maxima may have a varying magnitude of maxima. |
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We find a good contrast between maxima and minima in interference. |
A poor contrast is found between maxima and minima in the case of diffraction. |
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We find that there are a large number of fringes in interference. |
There are fewer fringes in diffraction. |
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In an interference pattern, the intensity at minima is usually very small or close to zero, which means minima is usually dark. Also, there is a very good contrast between the dark and bright fringe. |
In a diffraction pattern, we find that the intensity of minima is never zero, and there is poor contrast between a dark and the bright fringe or fringes. |
So, the above table clearly explains the difference between interference and diffraction in Physics. Now, let us differentiate between interference and diffraction of light:
Comparison Between Interference and Diffraction
|
Interference |
Diffraction |
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Interference is the spreading of waves behind obstacles. |
Diffraction is a phenomenon in which certain points of the space of wave oscillations are amplified while others are annulled or attuned. |
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Waves in an interference pattern stay away from the original route in the same elastic environment. |
Superposition of waves occurs in the same material environment. |
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The dimensions of cracks or obstacles should be of the same length. |
There is a constant phase difference between the waves that is the reason these waves are called coherent waves. We consider coherent waves in the diffraction patterns. |
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The direction of wave propagation never changes after superposition. |
The direction of wave propagation never changes after diffraction. |
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An obstacle or slit is not necessary for interference. |
An obstacle or slit is necessary for interference. |
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Fringe spacing is uniform in interference. |
Fringe spacing is non-uniform in diffraction. |