Malus's+law

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**Malus's law**
I 0 = Initial intensity of incident light in Wm -2 I = Intensity of transmitted light in Wm -2 θ = angle between transmitted ray and analyser (polarisers) in o.



where //c// is the speed of light, is the permittivity of free space , is the magnitude of the electric field in the electromagnetic wave, and is the angle between a polariser and an analyser

When θ = 0° ( or 180° ), I = I 0 cos 2 0° = I 0 That is the intensity of light transmitted by the analyzer is maximum when the transmission axes of the analyser and the polariser are parallel.

When θ = 90°, I = I 0 cos 2 90° = 0 That is the intensity of light transmitted by the analyser is minimum when the transmission axes of the analyser and polariser are perpendicular to each other.

media type="youtube" key="utY72MD-Ii4" width="560" height="315" [|Cowen Physics] Published on 7 Jan 2015 Youtube.com [|Cowen Physics] Youtube.com

media type="youtube" key="7im4f87NNSg" width="560" height="315" IB Physics SL revision - Wave Phenomena by Mitch Campbell pubilished on 2 Apr 2015

Brewster's law

Light is linearly polarised (plane polarisation) which means the polarisation is parallel to the surface when the angle between the ray of reflection and the ray of refraction is 90 o.