three identical polaroid sheet P1,P2 and P3 are oriented so that the pass axis of P2 and P3 are inclined - Physics - Wave Optics

Question

three identical polaroid sheet P1,P2 and P3 are oriented so that
the pass axis of P2 and P3 are inclined at the angle of 60 and 90
respectivly with the pass axis of P1 a monocromatic source S of
unpolarised light of intensity I0 is kept in front of polaroid
sheet P1 as shown in figure determine the intensities of light as
observed by the observer at O , when the polaroid P3 is rotated
with respect to P2 at angle θ=30 and 60 degree

Manoj Singh · Accepted Answer

Dear Student
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When unpolarised light passed through P1 then we will
get intinsity I02, its independent of angle
intensity of light after passing through P2 = I02cos260 =I08Initially angle between P2 and P3 is 30
 If we rotate P3 at angle 30 (anticlockwise) with respect P2
At this time angle between P2 and P3 is zero therefore we get intensity  I08
If we rotate P3 at angle 60 (anticlockwise) with respect P2
At this time angle between P2 and P3 is 30Now intensity = I08cos230 = 3I032Note: If unpolarised or circularly polarized light passed through polariser then output intensity is independent of angle between pass axis
Thank you