Problem 5.161

Natural light falls on a system of three identical in-line Polaroids, the principal direction of the middle Polaroid forming an angle \(\varphi=60^{\circ}\) with those of two other Polaroids. The maximum transmission coefficient of each Polaroid is equal to \(\tau=0.81\) when plane-polarized light falls on them. How many times will the intensity of the light decrease after its passing through the system?