MHT CET202523 Apr 2025Morning ShiftPhysicsWave OpticsActual
Two polaroids are oriented with their planes perpendicular to incident light and transmission axis making an angle 30^ with each other. What fraction of incident unpolarised light is transmitted? ( 30^ = 3 / 2 )
Options
- A57 5 %
- B17 5 %
- C27 5 %
- D37 5 %
Correct answer
D. 37 5 %
Step-by-step solution
A polarizer reduces the intensity of unpolarized incident light to I₁ = I₀ 2 , producing plane-polarized light. Subsequent transmission through a second polarizer at angle = 30^ follows Malus's Law: I₂ = I₁ ^2 . Substituting the known values gives I₂ = I₀ 2 ^2(30^ ) . Since 30^ = 3 2 , we compute ^2 30^ = 3 4 and obtain I₂ = 3 8 I₀ . The fraction transmitted is 3 8 , which corresponds to 37.5 % of the incident intensity. The correct choice is D .