Wave Optics

Three polaroid sheets \(P_1, P_2\) and \(P_3\) are kept parallel to each other such that the angle between pass axes of \(P_1\) and \(P_2\) is \(45^{\circ}\) and that between \(P_2\) and \(P_3\) is \(45^{\circ}\). If unpolarised beam of light of intensity \(128 \mathrm{~Wm}^{-2}\) is incident on \(P_1\). What is the intensity of light oming out of \(P_3\) ?