Polarised light

Light from a regular sources such as sunlight and lamplight is unpolarised. This means that the oscillations of the electric and magnetic waves that make up light occur in any plane. However, by using a polariser we can only allow a certain specific orientation of these EM waves through. Therefore, polarised light is defined as EM waves that oscillate in one plane ⁽¹⁾ . 

References:

⁽¹⁾ https://www.physicsclassroom.com/class/light/Lesson-1/Polarization

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