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Two Polaroids (polarizers that can polarize visible light) are aligned so that the light passing through them is a maximum. At what angle should one of them be placed so that the intensity is subsequently reduced by half?

1 Answer

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Let the intensity of light from the first polaroid is I_o

The intensity through the second polaroid is,


I=I_{\text{o}}\cos ^2(\theta)

where,


\theta\text{ is the angle between the }direction\text{ of polarisation of two polaroids,}

For the angle,


\theta=45^(\circ)

The intensity of light from the second polaroid is,


\begin{gathered} I=I_o\cos ^2(45^(\circ)) \\ I=I_(\circ)(\frac{1}{\sqrt[]{2}})^2 \\ I=(I_(\circ))/(2) \end{gathered}

Thus, the intensity of light from the second polaroid becomes half if the angle between the direction of polarization of two polaroids is 45 degree.

User Jhon Didier Sotto
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