BRAINCAKEPolarising Filters
A polarising filter (such as Polaroid) contains long-chain molecules lined up in one direction. It only lets through oscillations in one plane, along its transmission axis, and absorbs the rest.
When unpolarised light passes through a polarising filter (the polariser), the light that emerges is plane polarised. Its intensity is reduced to about half of the original, because the oscillations at right angles to the transmission axis are absorbed.
A second filter, called the analyser, can then be used to test the polarised light.
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More in Optics
- Forming an Image
- Image Calculations
- Magnification
- Plane Polarisation
- Polarisation by Reflection and Refraction
- Exam-style Question 1
- Exam-style Question 2
- Exam-style Question 3
All 21 lessons in Optics · All Edexcel AS-level Physics topics