What are the effects of wave barriers and gaps on diffraction?

Wave barriers and gaps affect diffraction by causing waves to bend around obstacles or spread out after passing through gaps.

When waves encounter a barrier or an obstacle, they tend to bend around it, a phenomenon known as diffraction. The extent of this bending depends on the size of the obstacle or the gap relative to the wavelength of the wave. If the obstacle or gap is much larger than the wavelength, the wave will bend slightly. However, if the obstacle or gap is comparable to or smaller than the wavelength, the wave will bend significantly.

For instance, when light waves (which have very short wavelengths) pass through a small gap or slit, they spread out or diffract, creating a pattern of light and dark bands. This is known as the diffraction pattern. The central band is usually the brightest because most of the light passes straight through the gap. The other bands are formed by light that has been diffracted to a greater extent.

Similarly, when sound waves (which have longer wavelengths) encounter a barrier, they bend around it. This is why you can still hear someone's voice even if they are standing behind a wall or a barrier. The sound waves are diffracting around the barrier to reach your ears.

In the case of water waves, when they pass through a gap in a barrier, they spread out in semi-circular waves. The narrower the gap, the more the waves spread out. This is why when a wave passes through a narrow opening into a harbour, it can spread out and fill the entire harbour.

In conclusion, wave barriers and gaps play a significant role in the diffraction of waves. The size of the barrier or gap relative to the wavelength of the wave determines the extent of the diffraction.