In: Physics
We saw in lecture that light waves can be polarized. Can sound waves be polarized? If so, give an example of polarized sound. If not, explain why not.
Sounds are longitudinal waves, they propagate through a medium in the form of compressions and rarefactions in one particular direction. A particular sound wave has the option to travel in one direction only. So the concept of polarisation is useless for sounds and for all similar longitudinal waves.
However, transverse waves like electromagnetic radiation propagate in the form of electric and magnetic fields perpendicular to each other. While the energy of the wave travels in one specific direction, the oscillations can happen in ANY plane. There could be multiple oscillations in multiple planes. Polarising the wave blocks all the oscillations except 1 of them. So the resulting wave will have only 1 oscillation of electric field in 1 plane along with its perpendicular magnetic field.
Example:
Transverse waves can be polarised, but longitudinal waves cannot. Light can be polarised, showing that it consists of transverse waves. Polarisation happens when light travels through a polarising filter (Polaroid filter). The filter only lets light wavesthrough if they are vibrating in the correct plane.