Physics 8B Lab 5-Properties of Light rev 4.0 Consider polarized light incident o
ID: 2269121 • Letter: P
Question
Physics 8B Lab 5-Properties of Light rev 4.0 Consider polarized light incident on a polarizer. Define 6, as the angle the polarization of the incoming light and the polarization axis of the polarizer. If the incident light has E-field amplitude, Eo then after the linear polarizer, the light will be in line with the polarization axis of the polarizer and have E-field amplitude E cos8. Since intensity of a light wave is proportional to its electric field squared, if the incident intensity is lo the intensity after the polarizer will be locos e. Consider unpolarized light incident on a polarizer. After the polarizer, the light will be in line with the polarization axis of the polarizer. But the intensity of light that is transmitted is different depending on all the possible values of . If you average over all possible values of , you find that the transmitted light after the polarizer has intensity 12 Activity 1: Single Polarizer white screen 1. Predict what you will see on the screen as you rotate the polarizer. Why? On the optical bench, line up the optical bench light, a single polarizer and the 2. Now turn on the bench light and rotate the polarizer. Was your prediction correct? Explain any differences. 3. Is the optical bench lamp polarized or unpolarized light? How do you know? 216Explanation / Answer
1. If the lamp is unpolarized source, we will get same intensity on rotation of the polarizer. The intensity will be Io/2.
This is because, the light has no particular orientation, hence it will not matter what is the orientation of polarizer, the output intensity will be same.
If the source is polarized, on rotating the polarizer, the intensity will decrease, eventually become zero, and then increase again. We will get a cos2 dependece of the output intensity.
2. Usually, bench lamps are unpolarized. Hence, we will see a constant output intensity. There will be no variation due to rotation of the polarizer.
3. Hence, the source is unpolarized due to reasons mentioned above.