'n' polarizing sheets are arranged such that each makes an angle 45° with the preceding sheet. Unpolarized light of intensity I is incident on this arrangement. The output intensity is I/64. The value of n is:
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Question

'n' polarizing sheets are arranged such that each makes an angle 45° with the preceding sheet. Unpolarized light of intensity I is incident on this arrangement. The output intensity is I/64. The value of n is:

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G1 Physics · Accepted Answer

After the first sheet, intensity is I/2. Every subsequent sheet at 45° gives another factor cos²45° = 1/2. Thus after n sheets, I(out)=I/2ⁿ. Since I/2ⁿ = I/64, 2ⁿ=64 and n=6.