Question

what happens to the magnectic vector of light when itss polarised??

Answer 1

The electric field and the magnetic field of a propagating electromagnetic field are related by Maxwell's equations. This is true for all polarization states. So say you have a circularly polarized field that is propagating through a linear polarizer. Before the polarizer one can write down the electric field for the circularly polarized field and then use the appropriate Maxwell equation to calculate the associated magnetic field. The polarizer will remove one linear polarization component, leaving only the orthogonal linear polarization. Again one can then write down the electric field for the resulting linearly polarized field and then use the appropriate Maxwell equation to calculate the associated magnetic field.