Question

Can sound waves be diffracted?

Answer 1

Diffraction is a phenomenon in which waves bend around the corners or openings to spread in a region of geometrical space. The larger the wavelength, the more the waves bend. Waves bend when the obstacle or opening is comparable to the wavelength of the wave.

Complete answer:
Diffraction is the phenomenon which is described as the bending of waves around an obstacle or corner into a region of geometrical shadow. It occurs when a wave strikes an opening or an obstacle in its path whose size is comparable to the wavelength of the wave.
The mathematical representation of diffraction is given by-
$d\sin \theta =n\lambda$
Here, $d$ is the length of the opening or the distance between the slits
$\theta$ is the angle of diffraction
$n$ is the order number for the maximum
$\lambda$ is the wavelength
When bending around the corners, the sharpness of diffraction increases with increase in wavelength and vice versa. The sound waves diffract around the corners or through door openings as we are able to hear the conversations going on in the next room. Some applications of diffraction of sound are-
Owls are able to communicate at long distances due to the fact that their hoots, which have long wavelengths, are able to diffract around forest trees.
Therefore, sound waves can be diffracted.

Note:
According to the Huygen’s each point on a wave acts as a source and hence is called secondary wavelets. The corners or opening through which diffraction takes place also acts as a source. The source of waves must be coherent. Sources are said to be coherent when the waves emitting from it have constant phase difference and same frequency.