Interference of light is a phenomenon where two or more light waves overlap and combine to form a new pattern of light intensity.
This happens because light behaves as a wave, with peaks (crests) and valleys (troughs). When waves meet at the same point, their effects add together:
- Constructive Interference:
- Occurs when the waves meet in phase (crests align with crests, troughs with troughs).
- Their amplitudes add up, producing a brighter or intensified light.
- Destructive Interference:
- Happens when the waves meet out of phase (crest meets trough).
- Their amplitudes cancel out, resulting in reduced brightness or even darkness.
Interference is best seen when the light waves are coherent (having a constant phase relationship), such as in a double-slit experiment or with laser light. It leads to patterns of alternating bright and dark fringes and provides strong evidence for the wave nature of light.