# Why Does an Unpolarised Light Incident on a Polaroid Get Linearly Polarised ? - Physics

Why does an unpolarised light incident on a polaroid get linearly polarised ?

How does one get linearly polarised light with the help of a polaroid?

#### Solution 1

When unpolarised light is passed through a polaroid crystal, only those vibrations of light pass through the crystal that are parallel to the axis of the crystal. All other vibrations will be absorbed by the crystal. In this way, the unpolarised light incident on a polaroid gets linearly polarised.

#### Solution 2

We get linearly polarised light with the help of a polaroid as shown below:

​The naked eye or the polariser cannot distinguish between unpolarised and plane polarised light. A crystal called analyser is used to analyse the nature of light.

If the axis of the polariser and the analyser are parallel to each other, the intensity of light is found to remain unaffected.

Concept: Polarisation
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