This preview shows pages 1–3. 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: pan (zp695) ch24-h2 chiu (56565) 1 This print-out should have 19 questions. Multiple-choice questions may continue on the next column or page find all choices before answering. 001 10.0 points A proton is briefly accelerated in the- y di- rection, as shown in the figure below. + A D C B a At which location(s) AD will electromag- netic radiation be detected a short time later? List all that apply, separated by commas. If none apply, enter none. Correct answer: A, B, C. Explanation: The radiative electric field is non-zero at locations A, B, and C. The radiative electric field along the axis of the acceleration (point D) is zero. 002 10.0 points A proton is accelerated in the direction shown by the arrow labeled a in the figure below. r a IV I VI V II III Which of the arrows labeled I-VI shows the direction of the vector a at the observation location indicated by the vector r ? 1. VI correct 2. V 3. II 4. I 5. IV 6. III Explanation: VI is the correct choice. 003 (part 1 of 3) 10.0 points A proton located at the origin is accelerated in the- y direction for a brief time. How much time passes before a detector located at . 85 m , , detects a radiative electric field? Use c = 3 10 8 m / s. Correct answer: 2 . 83333 10- 9 s. Explanation: The wave propagates at the speed of light. So c = distance t t = distance c = . 85 m 3 10 8 m / s = 2 . 83333 10- 9 s . 004 (part 2 of 3) 10.0 points What is the direction of the radiative electric field observed at this location? Choose the unit vector corresponding to this direction. 1. , , 1 2. , 1 , correct 3. 1 , , 4.- 1 , , 5. ,- 1 , 6. , ,- 1 pan (zp695) ch24-h2 chiu (56565) 2 Explanation: For a proton, the radiative electric field is opposite a , which is in the- y direction. Thus, at the given location, E rad is in the + y direction. 005 (part 3 of 3) 10.0 points If the accelerated particle had been an elec- tron instead of a proton, what would have been the direction of the radiative electric field at this location? Choose the unit vector corresponding to this direction. 1. , 1 , 2. 1 , , 3. , ,- 1 4. , , 1 5.- 1 , , 6. ,- 1 , correct Explanation: For an electron, the radiative electric field is in the same direction as a . Thus, at the given location, E rad is in the- y direction. 006 10.0 points An electric field acts on an electron, resulting in an acceleration of 1 . 2 10 17 m / s 2 for a short time. What is the magnitude of the radiative electric field observed at a location a distance of 2 cm away along a perpendicular to the direction of the acceleration? Use the following constants: c = 3 10 8 e = 1 . 6 10- 19 k = 1 4 = 9 10 9 N m 2 / C 2 ....
View Full Document
This note was uploaded on 02/21/2012 for the course PHY 303K taught by Professor Turner during the Spring '08 term at University of Texas at Austin.
- Spring '08