Diffraction is the bending of light waves around obstacles or through openings, which occurs when light encounters an obstruction or a slit. This phenomenon results from the interference between different parts of the light wave. The pattern formed is a result of the constructive and destructive interference between the different parts of the light wave passing through or around the obstacle.
Key Concept: Diffraction is closely related to the interference of light waves. When two or more waves overlap, they combine to form a resultant wave, depending on whether they are in phase (constructive interference) or out of phase (destructive interference). This behavior is key to diffraction patterns.