Destructive interference in light occurs when two or more light waves meet in such a way that their crests and troughs are exactly out of phase — meaning the crest of one wave aligns with the trough of another.
This opposite alignment causes the waves to cancel each other out, resulting in a reduction or complete cancellation of light intensity at that point.
Key points:
- It happens when the path difference between two waves is an odd multiple of half the wavelength.
- Destructive interference produces dark fringes or bands in an interference pattern.
- It demonstrates the wave nature of light, as only waves can combine to cancel each other.
This phenomenon is commonly observed in experiments like the double-slit experiment, thin films, and Newton’s rings, where alternating dark and bright patterns result from interference.