Question

What is meant by diffraction?

Answer 1

In order to solve this question, we are going to firstly define the diffraction of light, then, the phenomenon is explained by taking the example of the single slit diffraction and the mathematical formulation for the minima of diffraction is also calculated and shown for the single slit diffraction.

Complete step-by-step solution:
The diffraction is defined as the phenomena followed by waves whenever they come across any obstacle that leads to the bending of the light. The bending of light is in such a way that when it comes across the small openings or something, it illuminates that area instead of creating a shadow. However it is hard to separate diffraction from interference because they occur simultaneously. In fact interference can be interpreted as the superposition of various diffractions.
In the single-slit diffraction experiment, we can observe the bending phenomenon of light or diffraction that causes light from a coherent source to interfere with itself and produce a distinctive pattern on the screen called the diffraction pattern. The source size should be small enough and comparable to the wavelength of the light for the diffraction to be evident. For large slits, the diffraction is generally unnoticeable.
If we assume a slit of width$a$, with distance$D$ from the screen, and wavelength of light be, $\lambda$
The minima occurs at
$n\lambda = d\sin {\theta _n}$
Where the equation is for${n^{th}}$minima.

Note: It is important to note that the diffraction occurs through an aperture into the region of geometrical shadow of the obstacle/aperture. It has also been described by the Huygens–Fresnel principle that treats each point in a propagating wavefront as a collection of individual spherical wavelets.