Eli5 Why light waves require line of sight while sound waves do not?
In: 3
The key is wavelength.
Visible light wavelength is in the 0.00000001 m. This is very short.
Sound wavelengths are much longer. Normal speech is around 1-2 meter wavelength.
When a wave hits an corner it diffracts. This happens with waves of all types: light, sound, waves in water etc. It looks omething like this: https://web2.ph.utexas.edu/~coker2/index.files/waveobstacle-diffraction.gif
The amount of diffraction depends on the wavelength.
Short wavelength waves (like light) diffract very little.
Long wavelength waves (like sound) diffract very strongly.
So light that comes to a corner mostly keeps on going straight. But sound that hits corner will bend behind the corner.
So you can hear the sound coming from behind the corner but you can’t see light coming from behind the corner.
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