When a polaroid sheet is rotated between two crossed polaroids then the transmitted light intensity will be maximum for a rotation of :
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When a polaroid sheet is rotated between two crossed polaroids then the transmitted light intensity will be maximum for a rotation of :

G1 Physics · Accepted Answer

Let I₀ be the intensity of unpolarised light incident on the first polaroid. I₁ = I₀/2 Let θ be the angle between the 1st and 2nd polaroid. Then the angle between the 2nd and 3rd polaroid is: ϕ = 90° - θ I₂ = I₁ cos²θ = (I₀/2) cos²θ I₃ = I₂ cos²ϕ = (I₀/2) cos²θ sin²θ = (I₀/8) sin²2θ I₃ is maximum when: sin2θ = 1 ⇒ 2θ = 90° ⇒ θ = 45°