An unpolarized light of intensity I_o passes through polarizer and then through a certain optically active solution and finally it goes to analyser.…

An unpolarized light of intensity $\displaystyle I_{\mathrm{o}}$ passes through polarizer and then through a certain optically active solution and finally it goes to analyser. If the angle between analyser and polariser is $\displaystyle 0^{\circ}$ and intensity of light emerged from analyser is $\displaystyle \frac{3}{8} I_{\mathrm{o}}$, the angle of rotation of the light by the solution with respect to analyser is $\displaystyle \_\_\_\_$ degrees.