An unpolarised light of intensity 64 text{ Wm | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) Let the intensity of the unpolarised light be $I_0 = 64 	ext{ Wm}^{-2}$.After passing through the first polarizer, the intensity becomes $I_1 = \

Vedclass · Accepted Answer

$\frac{1}{2} \sin^{-1} \left( \frac{\sqrt{3}}{2} \right)$

Vedclass · Answer

(A) Let the intensity of the unpolarised light be $I_0 = 64 	ext{ Wm}^{-2}$.After passing through the first polarizer, the intensity becomes $I_1 = \frac{I_0}{2} = 32 	ext{ Wm}^{-2}$.Let $	heta$ be the angle between the transmission axes of the first and second polarizers.The intensity after the second polarizer is $I_2 = I_1 \cos^2 	heta = 32 \cos^2 	heta$.The angle between the first and third polarizer is $90^\circ$ (crossed).Therefore, the angle between the second and third polarizer is $(90^\circ - 	heta)$.The intensity after the third polarizer is $I_3 = I_2 \cos^2(90^\circ - 	heta) = I_2 \sin^2 	heta$.Substituting $I_2$, we get $I_3 = (32 \cos^2 	heta) \sin^2 	heta = 32 (\sin 	heta \cos 	heta)^2 = 32 \left( \frac{\sin 2	heta}{2} ight)^2 = 8 \sin^2 2	heta$.Given $I_3 = 6 	ext{ Wm}^{-2}$, so $8 \sin^2 2	heta = 6$, which means $\sin^2 2	heta = \frac{6}{8} = \frac{3}{4}$.Thus, $\sin 2	heta = \frac{\sqrt{3}}{2}$, which implies $2	heta = \sin^{-1} \left( \frac{\sqrt{3}}{2} ight)$.Therefore, $	heta = \frac{1}{2} \sin^{-1} \left( \frac{\sqrt{3}}{2} ight)$.

Similar Questions

$A$ polaroid is placed at $45^{\circ}$ to an incoming linearly polarized light of intensity $I_0$. The intensity of light passing through the polaroid after polarization will be:

An unpolarised beam of intensity $2 a^{2}$ passes through a thin polaroid. Assuming zero absorption in the polaroid,the intensity of emergent plane polarised light is

Which of the following statements indicates that light waves are transverse?

Define unpolarized light and polarized light.

Vedclass Test Series

Exam Paper Generator

Online Exam Module