Three polaroid sheets P₁, P₂ and P₃ are kept parallel to each other such that the angle between pass axes of P₁ and P₂ is 45^ and that between P₂ and P₃ is 45^ . If unpolarised beam of light of intensity 128 Wm ⁻² is incident on P₁ . What is the intensity of light coming out of P₃ ?

Step-by-step solution

The situation given in question can be shown as Here, I₀=128 Wm ⁻², ₁=45^ and ₂=45^ According to Malus's law, intensity of the light coming out of P₂ , I= I₀ 2 ² ₁ Similarly, intensity of light coming out of P₃ , aligned I^ &= I₀ 2 ² ₁ ² ₂ &= 128 2 ² 45^ ² 45^ &=64 1 2 1 2 =16 Wm ⁻² aligned