JEE Main202427 Jan 2024Evening ShiftPhysicsWave OpticsActual
When a polaroid sheet is rotated between two crossed polaroids then the transmitted light intensity will be maximum for a rotation of :
Options
- A60 °
- B30 °
- C90 °
- D45 °
Correct answer
D. 45 °
Step-by-step solution
Let I 0 be intensity of unpolarised light incident on first polaroid. I 1 = Intensity of light transmitted from 1 st polaroid = I 0 2 If θ be the angle between 1 st and 2 nd polaroid and ϕ be the angle between 2 nd and 3 rd polaroid, then θ + ϕ = 90 ° . . . 1 If I 2 = Intensity from 2 nd polaroid, I 2 = I 1 c o s 2 θ = I 0 2 c o s 2 θ If I 3 = Intensity from 3 rd polaroid I 3 = I 2 c o s 2 ϕ = I 1 cos 2 θ cos 2 ϕ = I 0 2 c o s 2 θ c o s 2 90 ° - θ = I 0 2 c o s 2 θ s i n 2 θ = I 0 2 2 sin θ cos θ 2 2 = I 0 8 sin 2