A beam of unpolarized light of intensity I₀ passes through a polarizer P₁ and then through an analyzer P₂ . The variation of the emergent intensity I from P₂ with the orientation angle of P₂ 's pass axis (measured from a fixed reference axis) is observed. It is found that the intensity I reaches a maximum value of 10 W/m ^2 at = 30^ and becomes zero at = 120^ . What is the value of the initial unpolarized light inten

Step-by-step solution

When unpolarized light of intensity I₀ passes through P₁ , the transmitted intensity is I₁ = I₀ 2 . When this light passes through P₂ , the emergent intensity is given by Malus's law: I = I₁ ^2( ) , where is the angle between the pass axes of P₁ and P₂ . The maximum intensity occurs when = 0^ (i.e., P₁ and P₂ are parallel). Thus, I_ max = I₁ = I₀ 2 . Given I_ max = 10 W/m ^2 , we have I₀ 2 = 10 I₀ = 20 W/m ^2 . Since the maximum occurs at = 30^ , the pass axis of P₁ is oriented at 30^ from the reference axis. When