Negative interference in physics occurs when two or more waves combine in such a way that their amplitudes partially or completely cancel each other out at certain points, resulting in a reduced overall amplitude in that region. This interference phenomenon is known as destructive interference.
One classic example of destructive interference is the double-slit experiment. In this experiment, a beam of coherent light is directed towards a barrier with two small slits. As the light passes through these slits, it diffracts and forms two separate wavefronts that spread out and overlap with each other on a screen placed behind the barrier.
At certain points on the screen, the peaks of one wave coincide with the troughs of the other wave, causing destructive interference. As a result, these points on the screen experience a reduction in the intensity of the light, forming dark fringes known as interference minima. This interference pattern is a consequence of the wave nature of light and provides evidence for the wave-particle duality of photons.
Destructive interference can also be observed in various other wave phenomena, such as in acoustics (sound waves), water waves, and electromagnetic waves. Understanding and manipulating interference effects are crucial in many areas of physics and engineering, ranging from optics and communications to quantum mechanics and waveguide design.