Download Polarization - Workshop 8 - Laboratory Review | PHY 102 and more Lab Reports Physics in PDF only on Docsity! PHY 102, Spring 2009, Workshop #8 1 Polarization Physics 102 Workshop #8 March. 19 –20, 2009 Name: ____________________________________ Instructor: _______________ Lab Partner(s): ____________________________ Time of Workshop: ________ General Instructions • Workshop exercises are to be carried out in groups of three. • One report per group is due by the end of the class. • Each week’s workshop session would typically contain three sections. The first two sections must be completed in class. The third section should be attempted if there is time. 1. A pre-lab reading and assignment section 2. Experiment section 3. Practice questions and problems Polarization A polarized wave is a wave in which there is only one vibration-direction. That is, if we are stationary at a chosen point in space, then the vibration-direction does not change, as time progresses. This unique direction is called the polarization-direction (PD) of the wave. The concept of a polarized wave is meaningful only for transverse waves (and hence light). Recall that for a transverse wave, it is required that the vibration-direction be perpendicular to the travel-direction. For any given travel direction, (let us say it travels along the positive x direction) every line in the plane perpendicular to the x axis fits the requirement. That is, each line in this plane (the yz-plane) is at right angles to the x direction. For unpolarized light, the vibration direction takes on, as time progresses, many directions in the yz- plane, in random fashion. For polarized light, there is just one direction in the yz-plane, (say, the +y direction), for which there is vibration. A filter is a sheet or set of sheets, made of material consisting of long, parallel chains of atoms. Further, when light is incident on the filter, the chains absorb any part of the energy of the light wave that vibrates parallel to the chain direction. The part of the wave that vibrates perpendicular to the chain direction passes through the polarizer. PHY 102, Spring 2009, Workshop #8 2 SOME SIMPLE EXPERIMENTS Overhead Lights Look at the room lights through one of the filters provided. Is the intensity of the light through the filter reduced, compared to the intensity that reaches your eye in the absence of a filter? Rotation of a Single Filter Does rotating the filter have any effect on the intensity of light from the overhead lights that reaches your eye? Nature of the Overhead Lights Consider your above observations. Do you conclude that the overhead lights emit polarized light or unpolarized light? Explain. Light through Two Filters Look at the room lights through two overlapping filters. Rotate one of the filters, keeping the other filter steady. Record below your observations on the intensity of light transmitted through both filters, as the rotation takes place.
