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Two polaroids P_(1) and P_(2) are set up so that their pass axis are crossed with respect to each other. A third polaroid P_(3) is now introduced between these two so that its pass axis makes an angle theta with the pass axis of P_1. A beam of unpolarised light of intensity I_(0) is incident on P_(1). if the intensity of light, that gets transmitted through the combination of three polaroids, be I find the ratio (I)/(I_(0)) when theta equals. (i) 30^(@), (ii) 45^(@). |
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Answer» Solution :The intensity of light, getting TRANSMITTED through the combination of three polaroids, is GIVEN by the relation `I=(I_(0))/(8)sin^(2)(2theta)` (i) `theta=30^(@)`, then `I_(30^(@))=(I_(0))/(8)sin^(2)(60^(@))=(I_(0))/(8)((sqrt(3))/(2))^(2)=(3I_(0))/(32)` (ii) If `theta=45^(@)`, then `I_(45^(@))=(I_(0))/(8)sin^(2)(90^(@))=(I_(0))/(8)*1=(I_(0))/(8)` `implies(I_(30^(@)))/(I_(45^(@)))=(3I_(0)//32)/(I_(0)//8)=(3)/(4)` |
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