An unpolarized light beam is incident on the polarizer of a polarization experiment and the intensit

Question

An unpolarized light beam is incident on the polarizer of a polarization experiment and the intensity of light beam emerging from the analyzer is measured as 100 Lumen. Now, if the analyzer is rotated around the horizontal axis (direction of light) by $30^{\circ}$ in clockwise direction, the intensity of emerging light will be _______ Lumen.\

Professor PC Thomas Classes · Answer

(75) : Consider the situation shown in figure.\ Now, the energy light has intensity\ $I=\left(\frac{I_{0}}{2}ight) \cos ^{2} 	heta$ (By Malus Law)\ $\Rightarrow I=\frac{I_{0}}{2} 	imes \cos ^{2} 30^{\circ}=\frac{I_{0}}{2} 	imes \frac{3}{4}=\frac{3}{8} I_{0}$\ $\Rightarrow \quad I=\frac{3}{8} 	imes 200=\frac{600}{8}=75$ lumen\