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1-9 - Create assignment 00224 Homework 9 Apr 08 at 6:09 pm...

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Create assignment, 00224, Homework 9, Apr 08 at 6:09 pm 1 This print-out should have 11 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. The due time is Central time. Hinged Mirrors 01 35:04, highSchool, numeric, > 1 min, wording- variable. 001 The reflecting surfaces of two intersecting flat mirrors are at an angle of 56 , as shown in the figure. A light ray strikes the horizontal mirror at an angle of 53 with respect to the mirror’s surface. 56 53 φ Figure is not drawn to scale. Calculate the angle φ . Correct answer: 68 . Explanation: Basic Concept: θ incident = θ reflected Solution: θ 1 θ 2 φ θ Figure is to scale. The sum of the angles in a triangle is 180 . In the triangle on the left we have angles θ , 180 - θ 1 2 , and 180 - θ 2 2 , so 180 = θ + 180 - θ 1 2 + 180 - θ 2 2 , or θ 1 + θ 2 = 2 θ . (1) In the triangle on the right we have angles θ 1 , θ 2 , and φ . 180 = θ 1 + θ 2 + φ , so θ 1 + θ 2 = 180 - φ . (2) Combining Eq. 1 and 2, we have φ = 180 - 2 θ = 180 - 2 (56 ) = 68 . As a matter of interest, in the upper-half of the figure the angles (clockwise) in the triangles from left to right are 37 , 37 , and 106 ; 74 , 34 , and 72 ; 108 , 19 , and 53 ; 127 , 19 , and 34 ; and in the lower-half of the figure the angles (counter-clockwise) in the triangles from left to right are 19 , 19 , and 142 ; 38 , 34 , and 108 ; 72 , 37 , and 71 ; 109 , 37 , and 34 . keywords: Perpendicular Mirrors 35:04, trigonometry, numeric, > 1 min, nor- mal. 002 Consider the case in which light ray A is in- cident on mirror 1 , as shown in the figure. The reflected ray is incident on mirror 2 and subsequently reflected as ray B. Let the an- gle of incidence (with respect to the normal)
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Create assignment, 00224, Homework 9, Apr 08 at 6:09 pm 2 on mirror 1 be θ A = 53 and the point of incidence be located 20 cm from the edge of contact between the two mirrors. 90 x A B mirror 1 mirror 2 θ A θ B What is the angle of the reflection of ray B (with respect to the normal) on mirror 2 ?
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