Question

To demonstrate the phenomenon of interference we require two sources which emit radiation of-

Answer 1

Hint: Interference of a wave is the phenomenon that generally happens when the two waves combine while traveling in a similar medium. The interference of waves creates the medium to take on a configuration that results from the net effects of the two individual waves simultaneously acting upon the particles of the medium. Two sources should release radiation of equal frequency and have a specific phase relationship for interference phenomenon.

Complete answer:
Interference of light is explained as: “When two or more light waves having the equal frequency, equal wavelength and equal amplitude join together in a medium at a position, they cancel or magnify the effect of each other at that position. This is termed interference of light waves”. The interference of light has two types: constructive and destructive.
When two light waves fall on each other so that the crest of a wave falls on the crest of another wave, and the trough of a wave falls on the trough of another wave, then the resultant wave has a higher amplitude and intensity. It is called constructive interference. In destructive interference, when two light waves fall on each other so that the crest of one wave is made to fall on the trough of another wave, then the amplitude and intensity of the resultant wave become zero.
There are some conditions for interference: The two light sources must be consistent; they must maintain a fixed phase concerning each other. The two sources should be monochromatic, that is, of a unique wavelength. The principle of superposition must be implemented.
To explain interference, coherent sources are required. Sources are called coherent when they release waves of approximately equal or equal frequency and a fixed phase difference throughout.

Note:
The primary difference between interference and diffraction is that interference is the superposition of a few secondary wavelets, while Diffraction is the superposition of a vast number of secondary waves. The alteration in the distribution of light energy due to the combination of two or more waves is called light interference.