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Polarisation
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About This Experiment
Discover how polaroid filters affect light intensity using Malus' law: I = I₀cos²θ, where θ is the angle between the filter's transmission axis and the incident light's polarisation direction. Light is an electromagnetic wave with electric field oscillations perpendicular to the direction of propagation, and polarisation refers to the orientation of these oscillations.
Unpolarised light has random orientations, but after passing through a polariser, it becomes linearly polarised. When this polarised light encounters a second filter (analyser), the transmitted intensity depends on the angle between their transmission axes. At 90°, no light passes through (crossed polarisers).