InterviewSolution
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InterviewSolution
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Explain Malus law and write it. |
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Answer» Solution :If the pass-axis of `P_(2)` makes an angle `theta` with the pass-axis of `P_(1)` then `VECE` vectors `(E_(0))` emerging from `P_(2)` makes an angle `theta` with pass axis of polaroid `P_(1)` which is shown in the FIGURE. By taking two component of vector `E_(0)` of plane POLARIZED light, (1) `E_(0)costheta` which is parallel to pass-axis of analyser `P_(1)`. `E_(0)SINTHETA` which is perpendicular to pass-axis of analyser `P_(1)`.  Component `E_(0)costheta` passes through `P_(1)` while component `E_(0)sintheta` is perpendicular to pass-axis of `P_(1)` so it is absorbed. Now intensity of light is proportional to square of amplitude intensity of light incident on analyser is `I_(0)propE_(0)^(2)` and intensity of light emerging from analyser is `Iprop(E_(0)costheta)^(2)`. Hence, intensity of light emerging from analyser, `(I)/(I_(0))=(E_(0)^(2)cos^(2)theta)/(E_(theta^(2)))=cos^(2)theta` `:.I=I_(0)cos^(2)theta` This is known as Malus law. |
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