MCQ
When a plane polarised light is passed through an analyser and analyser is rotated through $90^o ,$  the intensity of the emerging light
  • A
    Varies between a maximum and minimum
  • B
    Becomes zero
  • C
    Does not vary
  • Varies between a maximum and zero

Answer

Correct option: D.
Varies between a maximum and zero
d
When a ray of light with intensity $I$, is passed through an analyser, the new internsity $I ^{\prime}$ is given by,

$I^{\prime}=I \cos \theta$ where $\theta$ is the angle between the ray and the analyser.

Given that the when the analyser is rotated through $90^{\circ}$.

When angle will be $90^{\circ}$ the intensity will reach the minimum, i.e 0 .

So, when we start rotating the the initial angle was 0 , and the intensity was maximum. When we start rotating the intensity starts to decrease and then reaches the minimum at angle $90^{\circ}$ which is $zero.$

Hence, the correct answer is option $(D)$, i.e the intensity varies between a maximum and zero.

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