Unpolarized light of intensity 24 W/m² passes through three polarizers such that the transmission axis of the last polarizer is crossed with the first. Let (a) $α$ be the angle between the transmission axes of first two polarizers, such that intensity of final emerging light is 2.25 W/m² (b) $β$ be the angle between the transmission axes of first two polarizers, such that the intensity of final emerging light is maximum. The values of $α$ and $β$ are:

see full answer

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

30°, 60°

45°, 30°

30°, 45°

45°, 60°

answer is C.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

Detailed Solution

Let the angle between the transmission axes of first two polarizes is $θ$ . Then angle between second and third polarizers will be 90 - $θ$ . From Malus law:
$I = \frac{I_{0}}{2} \cos^{2} {θcos}^{2} (90 - θ) = \frac{I_{0}}{8} \sin^{2} (2 θ)$
From the given data:
$2.25 = \frac{24}{8} \sin^{2} 2 θ => \sin^{2} 2 θ = \frac{8 X 2.25}{24} = \frac{3}{4} =>= 30^{\circ}$