alleryIf polarised light of intensity I passes through a polariser whose axis makes angle θ with the polarisation direction, the transmitted intensity by Malus's law is
AI cos θ
BI × θ
CI sin θ
DI cos²θ
Answer & Solution
Correct answer: D. I cos²θ
1. Malus's law relates transmitted intensity of polarised light through a polariser.
2. I_t = I_0 × cos²θ, where θ is the angle between polarisation and analyser axis.
3. For θ = 0, I_t = I_0 (fully transmitted); for θ = 90°, I_t = 0.
4. This is the workhorse formula for photoelasticity and polarisation experiments.
_Source: syllabus Physics, Ch 10 "Wave Optics", §10.7_
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