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Unformatted text preview: PHYSICS 2306 TEST #1 1 October 1999 – 5 PM in Norris 136 17M01-03 (5:00 PM) and 18M01-03 (6:30 PM) 3”x5” Note Card and Calculator Allowed SOLUTIONS _________________________ ____________________ ________________________ (Name - Printed) (Student I.D.) (Signed Pledge - See Below) I pledge that the answers submitted by me represent only my work. Further, I pledge to refrain from communicating any information about this test to anyone until after the results of this test are returned. Please fill in the three entries specified above. Please record your answers to problems #1 through #25 on the op-scan answer sheet. Please remember to darken on the op-scan sheet the entries corresponding to your student I.D and to your group number [ groups 1, 2, 3 correspond to recitations at 8, 9, 10 AM, respectively; and groups 4, 5, 6 correspond to recitations at 2, 3, 4 PM, respectively ]. Do not put your name on the op-scan sheet. Please return the question sheets in a stapled packet to the appropriate stack on the front table specified by lecture time; and return the op-scan answer sheet to the other appropriate stack on the front table specified by lecture time. No credit will be given if any question or answer sheets are missing from your exam. Constants and Conversion Factors: charge of electron(magnitude) or proton: e = 1 . 6 x 10- 19 C Coulomb’s law constant: k e = ¼ πε o = 8.99 x 10 9 (N ⋅ m 2 /C 2 ) Permittivity of free space: ε o = 8 . 854 x 10- 12 (C 2 /N ⋅ m 2 ) Use as the speed of sound in air: v = 340 m/s Some Electric Field Expressions: A line of charge with charge per unit length λ , and an observation point along the line of charge a distance a from the close end and a distance b from the far end. a x E = k e λ⋅ (b-a)/ab b A semicircular arc, of radius d ,with charge per unit length λ ; at the center of the arc. E = 2k e λ /d SOLUTIONS 1. Two sinusoidal traveling waves are moving in the same direction. The waves have the same amplitude, speed, frequency, and wavelength; but they differ in phase by 90 ° . The superposition of these two disturbances results in a disturbance that is: Take y m to be the amplitude of one wave. y = 2y m ⋅ cos( ϕ /2) ⋅ sin(kx- ϖ t+ ϕ /2) = 2y m ⋅ cos(45 ° ) ⋅ sin(kx- ϖ t+ π /4) = 1.414y m ⋅ sin(kx- ϖ t+ ϕ /2) (1) a sinusoidal traveling wave with a frequency equal to twice the frequency of an individual wave, and with twice the amplitude of an individual wave. (2) a sinusoidal traveling wave with a wavelength equal to half the wavelength of an individual wave, and with twice the amplitude of an individual wave. (3) a sinusoidal traveling wave with the same frequency and wavelength as an individual wave, and with twice the amplitude as the amplitude of one of the individual waves....
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- Fall '06
- Physics, Wavelength, Fundamental physics concepts