Two Nicol prisms are oriented with their principal planes making an angle of 600 . The percentage of incident unpolarized light which passes through the system

Let say intensity of upolarized light is Io. Intensity of polarized light from first polarizer  =Io 2  After second polaroid , as per Malus' Law   I=Io 2cos2600=Io 8  hence, in percentage terms =Io 8 Io  ×100 = 12.5%