Polarization of light


When we throw a stone to water we see water ripples on the surface of water . Those ripples have one up wave and one down which is change over time . 



In case of light we have electromagnetic waves  are associated with electric and magnetic vectors which are mutually perpendicular to each other and also perpendicular to the direction of propagation .as you can see on the figures various combinations of E and B which are mutually perpendicular to each other and also perpendicular to the direction of propagation of wave .


Polarization refers to the phenomenon in which the oscillations of electric vector or magnetic vectors associated with ordinary e.m wave are restricted to just one direction . In other words unpolarized light can have electric vector or magnetic vectors associated with it oscillations in any direction while polarized light has its electric or magnetic vectors oscillating only in one direction .
The ordinary (unpolarized ) and polarized light represented in bellow figure


Such polarized light in which electric vectors are oscillating along one direction only is called linearly polarized or plane polarized . If the direction of oscillations of electric or magnetic vectors rotate with constant angular frequency we call it circularly polarized light .

If electric vector rotate but magnatude angular frequency not remain constant we call it circularly polarized light 

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