Answer:
45°
Explanation:
I = Polarized light after 3 filter = 0.5 W/m²
[tex]I_0[/tex] = Initial light intensity = 4 W/m²
The intensity of polarized light is given by
[tex]I=I_0cos^2Acos^245cos^245\\\Rightarrow A=cos^{-1}\sqrt{\dfrac{I}{I_0cos^245cos^245}}\\\Rightarrow A=cos^{-1}\sqrt{\dfrac{0.5}{4\times cos^245\times cos^245}}\\\Rightarrow A=45^{\circ}[/tex]
Hence, the angle relative to the vertical was the light initially polarized is 45°