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(a)Show using a proper diagram how unpolarised light can be linearly polarised by reflection from a transparent glass surface. (b) The figure shows a ray of light falling normallyon. the face AB of an equilateral glass prism having refractive index 3/2, placed A in water of refractive index 4/3. Will this ray suffer total internal reflection on striking the face AC? Justify your answer. |
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Answer» Solution :The angle of incidence of the ray . On STRIKING the face AC is `i= 60^(@) ` ( as from figure ) Also , relative refreactive index of glass . With RESPECT OT the surrounding water is ` mur=(3//2)/( 4//3) =(9)/(8) ` Also ` sin i= sin 60^(@) =(SQRT(3))/( 2) =( 1.732)/( 2) ` `= 0.866` For total internal reflection ,the requuired CRITICAL angle , in this case , is given by ` sin i_e = (1)/( mu ) = ( 8)/(9) = 0.89` ` therefore i lt i_3` Hence the ray would not suffer total internal reflection on striking the face AC [The students-may just write the two conditions needed for total internal reflection without analysis of the given case , student may be awarded 
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