How can he hear the sound?
Sound is a vibration that propagates as a mechanical wave of pressure and displacement, through some medium (such as air or water). Sometimes sound refers to only those vibrations with frequencies that are within the range of hearing for humans or for a particular animal.
The street cleaner above can hear the sound of the radio even though it comes from behind the wall. How come he can hear the sound?
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1 solution
since sound waves have a wavelength which is of the order of the dimensions of the corners of the wall hence the sound can be heard due to diffraction