Question

‘n’ polarizing sheets are arranged such that each makes an angle 45° with the proceeding sheet. An unpolarized light of intensity I is incident into this arrangement. The output intensity is found to be I/64. The value of n will be:

(1) 3

(2) 6

(3) 5

(4) 4

Answer 1

Correct option is (2) 6

After passing through first sheet

\(I_1 = \frac I2\)

After passing through second sheet

\(I_2 = I_1 \cos^2(45°) = \frac I4\)

After passing through n^th sheet

\(I_n = \frac I{2^n} = \frac I{64}\)

\(n = 6\)