How does wavelength affect the diffraction of waves?

Wavelength affects diffraction as shorter wavelengths diffract less and longer wavelengths diffract more when passing through an aperture or around an obstacle.

In more detail, diffraction is a wave phenomenon that occurs when a wave encounters an obstacle or a slit that is comparable in size to its wavelength. The wave bends around the obstacle or spreads out after passing through the slit, creating a diffraction pattern. The degree of diffraction, or the extent to which the wave spreads out, is directly related to the wavelength of the wave.

When a wave with a longer wavelength encounters an obstacle or slit, it bends more and spreads out more than a wave with a shorter wavelength. This is because the longer wavelength is closer in size to the obstacle or slit, and so it interacts more with it. This results in a wider diffraction pattern for longer wavelengths. Conversely, shorter wavelengths, being further from the size of the obstacle or slit, interact less and so diffract less, resulting in a narrower diffraction pattern.

This principle can be observed in everyday life. For example, lower frequency (and therefore longer wavelength) sounds can be heard around corners and through doors more easily than higher frequency sounds. This is because the longer wavelengths of the lower frequency sounds diffract more around the corners and through the doors.

In terms of light, which is also a wave, different colours of light have different wavelengths. Red light has a longer wavelength than blue light, and so it diffracts more. This is why, for example, when white light (which is a mix of all colours of light) passes through a prism, the red light bends more than the blue light, creating a rainbow effect.

IB Physics Tutor Summary: In summary, diffraction happens when waves bend around obstacles or through slits, and how much they spread out depends on their wavelength. Longer wavelengths diffract, or spread out, more because they're closer in size to these obstacles or slits, making a wider pattern. Shorter wavelengths spread out less, creating a narrower pattern. This affects everything from sound waves to light, influencing everyday phenomena like sound hearing around corners and the separation of light into colours through a prism.