Unpolarized light passes through three polarizing filters. The first filter bas
ID: 1570358 • Letter: U
Question
Unpolarized light passes through three polarizing filters. The first filter bas its transmission axis parallel to the z direction, the second has its transmission axis at an angle of 30.0 degree from the z direction, and the third has its transmission axis at an angle of 60.0 degree from the z direction. If the light that emerges from the third filter has an intensity of 804.0 W/m^2, what is the original intensity of the light? (Assume both angles are measured in the same direction from the +z axis.)Explanation / Answer
since the light is unpolarized, the intensity becomes half as it passes through the first one
I1 = I/2
when it passes through second one
I2 = I/2 cos^(theta)
I2 = I/2 cos^30 = 0.375 I
when it passes through the third one
I3 = I2 cos^(theta')
I3 = 0.375 I cos^60 = 0.09375 I
I = I3/0.09375 = 804/0.09375 = 8576 W/m^2
Hence, I = 8576 W/m^2