Question

Light and sound travel like a wave. Across a wall, we can hear two persons talking but can not see them. Why?

Answer 1

Sound waves have large wavelength compared to that of light, and for bending of any wave you need the dimensions of the object comparable to that of the wave, the thickness of a wall is comparable to that of sound waves, hence sound waves can easily bend, whereas for light to bend, walls should be very thin, as thin as 1 nanometer which is not possible hence light waves do not bend.