# Why does sound wave suffer more diffraction than light waves generally?

Why does sound wave suffer more diffraction than light waves generally?
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cokeman206
As a general guide, if we consider diffraction of a wave with wavelength $\lambda$ from an object of size d then the characteristic angle of the diffraction is given by:
$\mathrm{sin}\theta =O\left(\frac{\lambda }{d}\right)$
where the O() symbol means of order i.e. roughly the same as. So for example in a Young's slits experiment, where d is the slit spacing, the angle of the first maximum is given by:
$\mathrm{sin}\theta =\frac{\lambda }{d}$
$\mathrm{sin}\theta \approx 1.22\frac{\lambda }{d}$
It should now be obvious why diffraction of sound is so commonly observed in everyday life. The wavelength of sound is of order one metre, so objects around a metre in size will diffract it strongly. By contrast the wavelength of light is around half a micron, so you need to get the size down to the micron scale before light starts scattering strongly.