Unpolarized light of intensity I is incident | vedclass

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(A) When unpolarized light of intensity $I$ passes through the first polarizer $A$,the intensity becomes $I_A = I/2$.Since the emergent intensity afte

Vedclass · Accepted Answer

$\cos 	heta = (2/3)^{1/4}$

Vedclass · Answer

(A) When unpolarized light of intensity $I$ passes through the first polarizer $A$,the intensity becomes $I_A = I/2$.Since the emergent intensity after $B$ is $I/2$,the polarizers $A$ and $B$ must be parallel (angle $0^\circ$ between them).When a third polarizer $C$ is placed between $A$ and $B$ at an angle $	heta$ with $A$,the angle between $C$ and $B$ is $(90^\circ - 	heta)$ if $A$ and $B$ were crossed,but here they are parallel,so the angle between $C$ and $B$ is $	heta$.Using Malus' Law: $I_{final} = I_A \cos^2 	heta \cos^2 	heta = (I/2) \cos^4 	heta$.Given $I_{final} = I/3$,we have $(I/2) \cos^4 	heta = I/3$.$\cos^4 	heta = 2/3$.Therefore,$\cos 	heta = (2/3)^{1/4}$.

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