# 30 - Kapoor (mk9499) oldhomework 30 Turner (60230) 1 This...

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Unformatted text preview: Kapoor (mk9499) oldhomework 30 Turner (60230) 1 This print-out should have 15 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 (part 1 of 2) 10.0 points FM radio bands range from 88 MHZ through 108 MHz. The speed of light is 3 10 8 m / s. What is the wavelength for the FM radio band at 91 MHz? Correct answer: 3 . 2967 m. Explanation: Let : f 1 = 91 MHz and c = 3 10 8 m / s . The wavespeed is c = f 1 = c f 1 = 3 10 8 m / s 91 MHz 1 MHz 10 6 Hz = 3 . 2967 m . 002 (part 2 of 2) 10.0 points What is the wavelength for the FM radio band at 107 MHz? Correct answer: 2 . 80374 m. Explanation: Let : f 2 = 107 MHz . 2 = c f 2 = 3 10 8 m / s 107 MHz 1 MHz 10 6 Hz = 2 . 80374 m . 003 (part 1 of 4) 10.0 points Consider 3 polarizers #1, #2, and #3 ordered sequentially. The incident light is unpolar- ized with intensity I . The intensities after the light passes through the subsequent polar- izers are labeled as I 1 , I 2 , and I 3 respectively. See the sketch. I I 1 I 2 I 3 #1 #2 #3 Polarizers #1 and #3 are crossed such that their transmission axes are perpendic- ular to each other. Polarizer #2 is placed between the polarizers #1 and #3 with its transmission axis at 60 with respect to the transmission axis of the polarizer #1 (see the sketch). #1 #2 #3 60 After passing through the first polarizer, the intensity of the light I 1 is 1. I 1 = I 8 2. I 1 = 3 I 32 3. I 1 = 3 I 4 4. I 1 = I 32 5. I 1 = I 12 6. I 1 = I 16 7. I 1 = I 4 8. I 1 = 3 I 16 9. I 1 = 3 I 8 10. I 1 = I 2 correct Explanation: Kapoor (mk9499) oldhomework 30 Turner (60230) 2 Basic Concepts: Malus law states I = I cos 2 , where is the angle between the polarization of the light (before the light hits the polarizer) and the transmission axis of the polarizer. Solution: When unpolarized light falls on a polarizer, no matter what the orientation of the polarizer is, one half of the light is trans- mitted, and the polarization of the transmit- ted light is along the direction of the trans- mission axis of the polarizer (vertical in the present case). Thus the answer is I 1 = 1 2 I ....
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## This note was uploaded on 06/28/2009 for the course PHY 303L taught by Professor Turner during the Fall '08 term at University of Texas at Austin.

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30 - Kapoor (mk9499) oldhomework 30 Turner (60230) 1 This...

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