Three perfect linear polarizers are stacked normal to a central axis along which is incident a beam of natural light of intensity I 0 . If the first and last polarizers are crossed and if the middle

Question

Three perfect linear polarizers are stacked normal to a central axis along which is incident a beam of natural light of intensity I 0 ​ . If the first and last polarizers are crossed and if the middle one rotates at a rate 2 π rad / s about the axis, find the frequency (in 1/sec) of oscillation of intensity of emerging light.

TestHub · Accepted Answer

I 1 ​ = 2 I 0 ​ ​ ; I 2 ​ = 2 I 0 ​ ​ cos 2 ω t ; I 3 ​ = I 2 ​ sin 2 ω t I 3 ​ = 2 I 0 ​ ​ cos 2 ω t sin 2 ω t = 8 I 0 ​ ​ sin 2 2 ω t = 16 I 0 ​ ​ ( 1 − cos 4 ω t ) Angular frequency of oscillation = 4ω = 4 × 2π ⇒ 2 π f = 8 π ⇒ f = 4 /sec

Physics - Wave Optics Question with Solution | TestHub

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