A beam of unpolarised light passes through a tourmaline crystal A and then it passes through a tourmaline crystal B oriented so that its principal plane is parallel to that of A. the intensity of emergent light is $I_{0}$ . Now B is rotated by $45^{\circ}$ about the ray. The emergent light will have intensity:

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A beam of unpolarized 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 the emergent light is,

The correct option is C I04 According to Malus law: Intensity of plane polarized light when passed through polaroid B, I=I02(cos45∘)2=I02×12=I04 Hence, option (C) is correct.

A beam of unpolarized light of intensity $I_{0}$ is passed through a Polaroid $A$ and then through another Polaroid $B$ which is oriented so that its principal plane makes an angle of $45^{\circ}$ relative to that of $A$ . The intensity of the emergent light is,

The correct option is C $\frac{I_{0}}{4}$

According to Malus law: Intensity of plane polarized light when passed through polaroid $B$ ,

$I = \frac{I_{0}}{2} (cos 45^{\circ})^{2} = \frac{I_{0}}{2} \times \frac{1}{2} = \frac{I_{0}}{4}$

Hence, option $(C)$ is correct.