Question

Two polaroids are kept Crowe Weah other, NOW
one of them is rotated through an angle of 45
The percentage of incident light now transmitted
through the system is
1) 15% 2)25% 3) 50% 4) 60%​

Answer 1

This how answer came and answer is 25%

Answer 2

Solution :

Let the intensity be i. On passing through first polaroid, intensity reduces to half. That is, i/2. On passing through second polaroid intensity can be found by using Malus law.

$\implies$ $\sf{I = ( \frac{I_{0}}{2} )(cos\:45\degree) ^{2}}$

$\implies$ $\sf{I = \frac{I_{0}}{2} ( \frac{I}{ \sqrt{2} } ) ^{2}}$

$\implies$ $\sf{I = \frac{I_{0}}{4}}$

Now,

Percentage of incident light transmitted is:

$\implies$ $\boxed{\sf{\frac{1}{4} \times 100= 25\%} }$

Therefore,

Correct option: (2) 25%

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Answered by: Niki Swar, Goa❤️