How is interference formed with coherent wave sources?

Interference is formed with coherent wave sources when waves from these sources overlap and combine, creating a resultant wave.

Interference is a fundamental concept in wave physics, and it occurs when two or more waves meet while travelling along the same medium. In the context of coherent wave sources, these are sources that emit waves with a constant phase difference. This means that the waves are always in phase or always out of phase, leading to constructive or destructive interference respectively.

Constructive interference occurs when the crest of one wave meets the crest of another, or when the trough of one wave meets the trough of another. This results in the amplitude of the resultant wave being the sum of the amplitudes of the two interfering waves. This leads to a wave of greater intensity or brightness, in the case of light waves.

On the other hand, destructive interference occurs when the crest of one wave meets the trough of another. This results in the amplitude of the resultant wave being the difference of the amplitudes of the two interfering waves. This leads to a wave of lesser intensity or even complete darkness, in the case of light waves.

The formation of interference patterns from coherent wave sources is a key principle behind many scientific and technological applications. For instance, in the double-slit experiment, light from a single source is split into two coherent sources by passing it through two closely spaced slits. As the light waves from the two slits overlap on a screen, they interfere to form a pattern of bright and dark fringes. This experiment provides evidence for the wave nature of light.

In summary, interference is formed with coherent wave sources when the waves they emit overlap and combine. The nature of the resultant wave, whether it is of greater or lesser amplitude, depends on whether the interference is constructive or destructive. This is determined by the phase relationship between the interfering waves, which is constant for coherent sources.