What is Huygens' principle?

Huygens' principle states that every point on a wavefront can be considered as a source of secondary waves.

Huygens' principle is a fundamental concept in wave theory that was proposed by Dutch physicist Christiaan Huygens in the 17th century. It states that every point on a wavefront can be considered as a source of secondary waves, which spread out in all directions at the same speed as the original wave. These secondary waves then interfere with each other to produce the overall wave pattern.

Huygens' principle is based on the idea that waves are propagated by the continuous emission of new waves from each point on the wavefront. This means that the wavefront can be thought of as a collection of tiny wavelets, each of which spreads out in all directions and interferes with the wavelets around it.

One of the key implications of Huygens' principle is that it can be used to explain the phenomenon of diffraction, which occurs when waves encounter an obstacle or pass through a narrow aperture. In these situations, the wavefront is disrupted and secondary waves are emitted from each point on the new wavefront, causing the wave to spread out and bend around the obstacle or aperture.

Overall, Huygens' principle is a powerful tool for understanding the behaviour of waves and has applications in a wide range of fields, from optics and acoustics to seismology and oceanography.