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Name one device for producing polarized light. Draw a graph showing the dependence of intensity of transmitted light on the angle between polarizer and analyser. |
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Answer» Solution :Nicol prism or calcite prism , According to Law of Malus, when a beam of completely plane polarized light is incident on an analyser, the resultant intensity of light `(I)` transmitted from the analyser varies directly as the square of the cosine of the angle `(theta)` between planes of TRANSMISSION of analyserand polarizer, (Law of Malus) i.e.,`I prop cos^(2)theta and I = I_(0) cos^(2) theta`...(i) where `I_(0) =` intensity of the light from polariser From (i), we note that if the transmitted axes of polariser and analyser are parallel (i.e. `theta = 0^(@) or 180^(@)`), then `I = I_(0)`. It means the intensity of transmitted light is maximum. When the transmission axes of polariser and analyser are prependicular (i.e. `theta = 90^(@)`), then `I = I_(0) cos^(2) 90^(@) = 0`. It means the intensity of transmitted light is zero. On plotting a GRAPH between `I and theta` as given by RELATION (i), we get the CURVE as shwon in Fig. 
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