[填空题]
Unpolarized light passes through five k+ rtq( p+y ezf23s/wfsuccessive Polaroid sheets, p5 qa, r7ri:fvl/okccoj )9k2 each of whose axis make2al9kroijp)kq r f7o5v/ c:,cs a 45$^{\circ}\,$ angle with the previous one. What is the intensity of the transmitted beam? $I_0$
