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A beam of unpolarised light of intensity I0 is passed through a polaroid A and then through another polaroid B which is oriented so that its principal plane makes an angle of 45 relative to that of A. The intensity of emergent light is:
(3) I0/4
After A (unpolarised in): I1= I02
After B (Malus's law): I2=I1 2 45
= I02 12= I04
Answer: (3)
In a double slit experiment shown in figure, when light of wavelength 400 nm is used, dark fringe is observed at P. If D=0.2 m, the minimum distance between the slits S1 and S2 is mm. [figure]
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