In Figure (a) below, unpolarized light is sent into a system of three polarizing
ID: 1414110 • Letter: I
Question
In Figure (a) below, unpolarized light is sent into a system of three polarizing sheets. The angles 1, 2, and 3 of the polarizing directions are measured counterclockwise from the positive direction of the y axis (they are not drawn to scale). Angles 1 and 3 are fixed, but angle 2 can be varied. Figure (b) gives the intensity of the light emerging from sheet 3 as a function of 2. (The scale of the intensity axis is not indicated.) What percentage of the light's initial intensity is transmitted by the system when 2 = 48o?
Explanation / Answer
Let initial intensity of light = Io
Intensity of light from P1 = Io/2
Intensity of light from P2 = (Io/2) * cos2(48)
= 0.2238 * Io
Intensity of light from P3 = (0.2238 * Io) * cos2(48)
= 0.1002 * Io
=> percentage of the light's initial intensity is transmitted by the system = (0.1002 * Io)/Io * 100%
= 10.02 %