Two polaroids are placed in the path of an un | vedclass

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

Question

(A) When unpolarised light of intensity $I_0$ passes through the first polariser,it becomes linearly polarised with intensity $I_1 = I_0 / 2$.Since th

Vedclass · Accepted Answer

$\left(\frac{I_0}{8}ight) \sin^2 2	heta$

Vedclass · Answer

(A) When unpolarised light of intensity $I_0$ passes through the first polariser,it becomes linearly polarised with intensity $I_1 = I_0 / 2$.Since the first and second polaroids were initially crossed (angle $90^{\circ}$),the third polaroid is placed at an angle $	heta$ with the first and $(90^{\circ} - 	heta)$ with the second.According to Malus' Law,the intensity after the second (middle) polariser is $I_2 = I_1 \cos^2 	heta = (I_0 / 2) \cos^2 	heta$.The intensity after the third (last) polariser is $I_3 = I_2 \cos^2(90^{\circ} - 	heta) = (I_0 / 2) \cos^2 	heta \sin^2 	heta$.Using the identity $\sin 2	heta = 2 \sin 	heta \cos 	heta$,we have $\sin^2 2	heta = 4 \sin^2 	heta \cos^2 	heta$.Therefore,$I_3 = \frac{I_0}{2} \cdot \frac{\sin^2 2	heta}{4} = \frac{I_0}{8} \sin^2 2	heta$.

Similar Questions

$A$ $20 \ cm$ length of a certain solution causes right-handed rotation of $38^{\circ}$. $A$ $30 \ cm$ length of another solution causes left-handed rotation of $24^{\circ}$. The optical rotation caused by a $30 \ cm$ length of a mixture of the above solutions in the volume ratio $1:2$ is

In the propagation of light waves,the angle between the direction of vibration and the plane of polarization is ....$^o$.

Vedclass Test Series

Exam Paper Generator

Online Exam Module