(1) In this experiment you observed that the intensity of light transmitted through a system of...


(1) In this experiment you observed that the intensity of light transmitted through a system of two polarizers with polarization axes perpendicular to each other drops down to zero. Imagine a system of three polarizers that have their axes at 45 degrees angles to the next one, so that the first and the third have their axes perpendicular. In other words, if the first polarizer has its axis vertical, the second is at 45 degrees, and the third has the axis horizontal. Predict, what percentage of the light that the first polarizer passed through will pass through the third one in such system. WIll it be zero? IF not what will it be? Explain your reasoning.

(2) In this experiment you observed that the observed intensity of light from a lightbulb decreases with the the distance like inverse square. On the other hand the light beam of a laser does not change intensity appreciably over very long distances. Explain why.

Application of Malu's Law and Angular Divergence

Malu's law says that the intensity of a plane polarized light passing through another polarizer with its transmission axis making an angle {eq}\theta {/eq} with the plane of vibration of the polarized light is proportional to {eq}\cos ^2 \theta {/eq}. So the transmitted intensity can be expressed as {eq}I_t = I_i \cos^2 \theta {/eq}. Here {eq}I_i, \ \ I_t {/eq} are the incident intensity of the plane polarized light and transmitted intensity of the polarized light respectively. Angular divergence is the measure of spreading of a light laterally when it moves in a medium.

Answer and Explanation: 1

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Given points

  • First polarizer vertical, second one at 45 degree with the vertical, and third one is again at vertical.

So the angle between second...

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Polarization of Light & Malus's Law


Chapter 15 / Lesson 6

Polarization is essentially filtering out the chaotic light-wave oscillations to achieve a more clear, and 'polar' experience of light. Explore how glasses, screens, and radios polarize, and understand Malus's law, which calculates the way to dim light to polarize effectively.

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