## College Physics (4th Edition)

The fraction of the incident light intensity that is transmitted is $\frac{1}{4}$
Since the light is unpolarized initially, the intensity of the light after passing through the first polarizer is $\frac{I_0}{2}$ We can use the law of Malus to determine the intensity of the light after passing through the second polarizer. $I = \frac{I_0}{2}~cos^2(45^{\circ}) = \frac{1}{4}\times I_0$ The fraction of the incident light intensity that is transmitted is $\frac{1}{4}$