Two Nicol prisms are oriented with their principal planes making an angle of ${60}^0$ . The percentage of incident unpolarized light which passes through the system

$$\begin{gathered} Let say intensity of upolarized light is I_o. \\ Intensity of polarized light from first polarizer =\frac{I_o }{2} \\ After second polaroid , as per Malus\text{'} Law \\ I=\frac{{\displaystyle I_o }}{{\displaystyle 2}}{\cos }^2{60}^0=\frac{I_o }{8} \\ hence, in percentage terms =\frac{\frac{I_o }{8}}{ I_o} \times 100 = 12.5\% \end{gathered}$$