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Unformatted text preview: luu (nml299) – WH04 – markert – (58710) 1 This print-out should have 20 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. 001 10.0 points Semiconductors such as silicon are used to fabricate solar cells—devices that generate electricity when exposed to sunlight. A silicon solar cell with index of refraction, n 3 = 3 . 5, is coated with a transparent thin film with index of refraction, n 2 = 1 . 29, for this pur- pose. Above the device is air which has index of refraction, n 1 = 1. See the figure below. #1 #2 t n 1 n 2 n 3 Determine the minimum film thickness that produces the least reflection at a wavelength of 500 nm. Answer in units of nm. 002 (part 1 of 2) 10.0 points Consider a horizontal plane of thin film with a thickness t . This film is located between air and water (see the sketch). The index of refraction of the film is 1 . 5 and the index of refraction of water is 1 . 33. The wavelength of the incident wave in the air is λ , and its frequency in air is f = c λ . Air Water t n 1 n 2 Find the wavelength of the light in the wa- ter. 1. λ water = n 2 λ 2. λ water = n 2 n 1 λ 3. λ water = 1 n 1 λ 4. λ water = n 1 n 2 λ 5. λ water = n 1 λ 6. λ water = 1 n 2 λ 003 (part 2 of 2) 10.0 points The frequency of the light in the water will 1. decrease . 2. stay the same . 3. increase . 004 10.0 points Two charged particles of equal magnitude (- Q and + Q ) are fixed at opposite corners of a square that lies in a plane (see figure be- low). A test charge- q is placed at a third corner....
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This note was uploaded on 09/22/2010 for the course PHY 58710 taught by Professor Markert during the Spring '09 term at University of Texas.
- Spring '09