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(a) Unpolarised light of intensity I_(0) passes through two polaroids P_(1) and P_(2) such that pass axis of P_(2) makes an angle theta with the pass axis of P_(1), Plot a graph showing the variation of intensity of light transmitted through P_(2) as the angle theta varies from zero to 180^(@). (b) A third polariod P_(3) is placed between P_(1) and P_(2) with pass axis of P_(3) making an angle beta with that of P_(1). If I_(1), I_(2) and I_(3) represent the intensities of light transmitted by P_(1), P_(2) and P_(3) determine the values of angle theta and betafor which I_(1)=I_(2)=I_(3). |
Answer» Solution :(a) The REQUIRED GRAPH WOULD have the form shown as :  Using `I_(2)=I_(1)cos^(2)theta` (b) `I_(1)=` Light TRANSMITTED by `P_(1)` `I_(3)=` Light transmitted by `P_(3)=I_(1)cos^(2)beta` `I_(2)=` Light transmitted by `P_(2)=I_(3)cos^(2)(theta-beta)` `:.I_(2)=I_(3)` `I_(1)cos^(2)beta.cos^(2)(theta-beta)=I_(1)cos^(2)beta` `theta=beta` Also `I_(1)=I_(2)` `I_(1)=I_(1)cos^(2)theta` or `cos^(2)theta=1` `:.theta=0^(@)` or `pi` Therefore `beta=0^(@)` or `pi` |
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