This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Platt, David Homework 30 Due: Nov 21 2005, 4:00 am Inst: Ken Shih 1 This printout should have 9 questions. Multiplechoice questions may continue on the next column or page find all choices before answering. The due time is Central time. 001 (part 1 of 1) 10 points Consider two ways that light might hypothet ically get from its starting point S to its final point F by being reflected by a mirror at ei ther point A or point B. Since light travels at a fixed speed in air, the path of the least time will also be the path of the least distance. S F A B C 44 cm 44 cm 23cm 23cm Show by calculation that the path SBF is shorter than the path SAF and record the difference in the path lengths. Correct answer: 14 . 6585 cm. Explanation: Given : SA = 23 cm and , AB = 44 cm . The path SBF is SBF = p SA 2 + AB 2 + p BC 2 + CF 2 = 2 p SA 2 + AB 2 = 2 q (23 cm) 2 + (44 cm) 2 = 99 . 2975 cm . The path SAF is SAF = SA + p AC 2 + CF 2 = (23 cm) + q (88 cm) 2 + (23 cm) 2 = 113 . 956 cm . The path difference is SF = SAF SBF = (113 . 956 cm) (99 . 2975 cm) 14 . 6585 cm . 002 (part 1 of 2) 10 points 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) on mirror 1 be A = 41 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 A B What is the angle of the reflection of ray B (with respect to the normal) on mirror 2 ? Correct answer: 49 . Explanation: If the angle of the incident ray A is A , the angle of reflection must also be A . Since the mirrors are perpendicular to each other, angle B is equal to 90  A B = 90  A = 90  41 = 49 ....
View Full
Document
 Fall '08
 Turner
 Physics, Work

Click to edit the document details