JEE Main2014PhysicsWave OpticsActual
Two beams, A and B of plane polarized light with mutually perpendicular planes of polarization are seen through a polaroid. From the position when the beam A has maximum intensity (and beam B has zero intensity), a rotation of polaroid through 30 o makes the two beams appear equally bright. If the initial intensities of the two beams are I A and I B respectively, then I A I B equals :
Options
- A3
- B3 2
- C1
- D1 3
Correct answer
D. 1 3
Step-by-step solution
I A cos 2 θ = I B cos 2 9 0 - θ I = I 0 cos 2 θ by malus equation ∴    I A I B = tan 2 θ = 1 3 where θ = 3 0 o