1. Learn how to determine the index of refraction of a material experimentally. 2. Learn to draw a ray diagram for refraction phenomena and for total internal reflection. I. APPLICATION EXPERIMENT: INDEX OF REFRACTION Determine the index of refraction of an unknown transparent material. Remember that you need to use two independent methods. Hint: One method can involve ideas about total internal reflection. Rubrics you're being scored on in this experiment: . . _ _ _ A10, D2, D4, D5, 62 Available equrpment: 2 samples of unknown materials (one semi-Circle, one trapezoid), ruler/meter stick, light source, paper, whiteboard, desk lamp (so the Rubrics attached at end of lab room can be left dark) For each experiment, include the following in your writeup: a) Choose which ofthe two samples you would like to determine the index of refraction of. If you wish to change your mind later on in the lab, that's fine, but you need to use the same sample for both methods (the two samples might not be made of the same material). b) Devise and write an outline of your procedure. Include a labeled diagram of your setup and a ray diagram. c) Describe the mathematical procedure you will use to determine the index of refraction. d) List the assumptions you are making. Why do you think that these assumptions are valid? Explain how each assumption could affect the outcome (will it make the index of refraction smaller, larger, or randomly different than the actual value?) e) List sources of experimental uncertainty. How will you estimate these uncertainties? Hint: Don'tjust use half the smallest increment unless you are sure that's appropriate. What is the largest source of the uncertainty? Take steps to minimize it f) Perform the experiment. Record your observations in an appropriate format. g) What is the result of your experiment? When finished with both experiments, compare the two values you obtained for the index of refraction. Decide ifthese are consistent or not. lfthey are not consistent, discuss possible reasons (explain the inconsistency in terms of the assumptions you made). Look at your experimental uncertainties and the assumptions you made. Devise some improvements to your experiment. Perform the experiment again using the improvements. What are your new results? Are they consistent now? ll. WHY DID WE DO THIS LAB? 1. Write a brief paragraph describing how you can use your assumptions to analyze the discrepancy between two inconsistent results. 2. What is the acceptable percentage for the discrepancy between two results? Careful