# Four polaroids are placed such that the optic axis of each is inclined at an angle of 30^(@) with the optic axis of the preceding one. If unpolarise

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Four polaroids are placed such that the optic axis of each is inclined at an angle of 30^(@) with the optic axis of the preceding one. If unpolarised light of intensity I_(0) falls on the first polaroid, the light transmitted from the fourth is
A. I_(0)
B. I_(0)//16
C. 0.21 I_(0)
D. none

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After first, I_(1)=I_(0)/2
After second, I_(2)=I_(1) cos^(2) 30^(@)=I_(0)/2xx3/4=(3I_(0))/8
After third, I_(3)=I_(2) cos^(2) 30^(@)=(3I_(0))/8xx3/4=(9I_(0))/32
After fourth, I_(3) cos^(2) 30^(@)=(9I_(0))/32xx3/4=27/128I_(0)=0.21I_(0)