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Unformatted text preview: segovia (cs39966) Homework 8 Spurlock (14441) 1 This printout should have 84 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. 001 10.0 points The reflecting surfaces of two intersecting flat mirrors are at an angle of 64 , as shown in the figure. A light ray strikes the horizontal mirror at an angle of 48 with respect to the mirrors surface. 64 48 Figure is not drawn to scale. Calculate the angle . Correct answer: 52 . Explanation: Basic Concept: incident = reflected Solution: 1 2 Figure is to scale. The sum of the angles in a triangle is 180 . In the triangle on the left we have angles , 180  1 2 , and 180  2 2 , so 180 = + 180  1 2 + 180  2 2 , or 1 + 2 = 2 . (1) In the triangle on the right we have angles 1 , 2 , and . 180 = 1 + 2 + , so 1 + 2 = 180  . (2) Combining Eq. 1 and 2, we have = 180  2 = 180  2 (64 ) = 52 . As a matter of interest, in the upperhalf of the figure the angles (clockwise) in the triangles from left to right are 42 , 42 , and 96 ; 84 , 26 , and 70 ; 110 , 22 , and 48 ; 132 , 22 , and 26 ; and in the lowerhalf of the figure the angles (counterclockwise) in the triangles from left to right are 22 , 22 , and 136 ; 44 , 26 , and 110 ; 70 , 42 , and 68 ; 112 , 42 , and 26 . 002 (part 1 of 3) 10.0 points Light of wavelength 634 nm in vacuum passes through a piece of silica (index of refraction 1 . 465). Find the speed of light in silica. Correct answer: 2 . 04636 10 8 m / s. Explanation: The speed of light in silica, v n can be easily obtained from the equation n = c v n . segovia (cs39966) Homework 8 Spurlock (14441) 2 We have v n = c n = 2 . 99792 10 8 m / s 1 . 465 = 2 . 04636 10 8 m / s . 003 (part 2 of 3) 10.0 points What is the wavelength of this light in silica? Correct answer: 432 . 764 nm. Explanation: We use the equation n = n to calculate the wavelength n in silica, noting that we are given the wavelength in vacuum to be = 634 nm : n = n = 634 nm 1 . 465 = 432 . 764 nm . 004 (part 3 of 3) 10.0 points Calculate the frequency of the light. Correct answer: 4 . 72859 10 14 Hz. Explanation: From the formula n = v n T n = v n f n (where T n is the period of the light wave in a medium with index of refraction n ) we obtain that the frequency is f n = v n n = 2 . 04636 10 8 m / s 4 . 32764 10 7 m = 4 . 72859 10 14 Hz . 005 10.0 points A ray of light is incident at an angle of 57 . 9 on the surface of a piece of crown glass whose index of refraction is 1 . 52 ....
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This note was uploaded on 11/10/2011 for the course PHYSICS 303L taught by Professor Hoffman during the Fall '11 term at University of Texas at Austin.
 Fall '11
 HOFFMAN
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