Polarisation of light.... With light, the elctric and magnetic fields are perpendicular to the direction of wave travel - but my text book says that these also exist in every plane, forming almost like a cylinder. This is what means it can be polarised. But what causes this? ie - what are the electrons doing to cause the elctric field to be in all directions? Further more, what happens to the magnetic fields when light is polarised - does this remain perpendicular to the elctric field remaining? Thanks in advance.