Light of original intensity I0 passes through two ideal polarizing filters having their...

Light of original intensity I₀ passes through two ideal polarizing filters having their polarizing axes oriented as shown in Fig. E33.28. You want to adjust the angle Φ so that the intensity at point P is equal to I₀/10. (a) If the original light is unpolarized, what should Φ be? (b) If the original light is linearly polarized in the same direction as the polarizing axis of the first polarizer the light reaches, what should Φ be?