Polarisation is the process by which the oscillations are made to occur in one plane only. This is done by passing the waves through a 'grid' so that only the waves that can fit through the slits can continue through: This idea is used in Polaroid glasses to reduce the amount of light able to reach the eye.
It is the phenomena in which when light wave move in one plain property  of certain electromagnetic radiation in which the direction and magnitude of the vibrating electric field are related in a specified way .
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