CH24 HW3 - WebAssign Ch24 HW3 S2010 (Homework) Kiyaniah...

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Unformatted text preview: WebAssign Ch24 HW3 S2010 (Homework) Kiyaniah Tilghman PY 208, section 003M, Spring 2010 Instructor: Keith Weninger Current Score : 11 / 18 Due : Monday, April 26, 2010 12:30 PM EDT About this Assignment Extension Requests Question Points 12345 0/2 0/1 0/2 6/7 5/6 Total 11/18 (61.1%) Description Sinusoidal radiation; energy and momentum in radiation; effect of radiation on matter Instructions Reading: Sec. 24.4-24.6 The due date for this assignment is past. Your work can be viewed below, but no changes can be made. 1. –/2 points Notes Question: MI3 24.X.038 A particular AM radio station broadcasts at a frequency of 1040 kilohertz. What is the wavelength of this electromagnetic radiation? (No Response) 288 m How much time is required for the radiation to propagate from the broadcasting antenna to a radio 5 km away? (No Response) 1.67e-05 s 2. –/1 points Notes Question: MI3 24.X.038.01 Radiation Which of the following are true for sinusoidal radiation? The radiation travels perpendicular to the electric field. The electric field and the magnetic field have the same magnitude at the same point in space. The electric field is perpendicular to the magnetic field. The radiation pattern does not change with time. The radiation pattern does not change with distance. The radiation travels perpendicular to the magnetic field. The source of the radiation is oscillating charges. Oscillating charges are not accelerating. The propagation direction of the radiation can be determined from the right hand rule. 3. –/2 points Notes Question: MI3 24.X.039 The wavelength of yellow light is about 575 nm (1 nanometer = 1 ! 10–9 m). What are the frequency and period of the light waves? f = (No Response) 5.22e+14 s-1 T = (No Response) 1.92e-15 s 4. 6/7 points All Submissions Notes Question: MI3 24.X.036 (a) If the electric field inside a capacitor exceeds about 3 106 V/m, the few free electrons in the air are accelerated enough to trigger an avalanche and make a spark. In the spark shown in the diagram, electrons are accelerated upward and positive ions are accelerated downward. Which arrow best indicates the direction of propagation of electromagnetic radiation reaching location A? g g Which arrow best indicates the direction of propagation of electromagnetic radiation reaching location C? d d What is the direction of the radiative electric field observed at location A? a a What is the direction of the radiative electric field observed at location C? b b What is the direction of the radiative magnetic field observed at location A? k k What is the direction of the radiative magnetic field observed at location C? j j If you are at location A, d = 4 meters to the left of the capacitor, how long after the initiation of the spark could you first detect a magnetic field? (No Response) 1.33e-08 seconds 5. 5/6 points All Submissions Notes Question: MI3 24.P.043 Radiation and a copper wire A slab (pulse) of electromagnetic radiation that is h = 15 cm thick is propagating downward (in the - y direction) toward a short horizontal copper wire located at the origin and oriented parallel to the z axis, as shown in the figure. (a) The direction of the electric field inside the slab is out of the page (in the +z direction). What is the direction of the magnetic field inside the slab? -x -x (b) You stand on the x axis at location < 12, 0, 0 > m, at right angles to the direction of propagation of the pulse. Your friend stands on the z axis at location < 0, 0, 12> m. The pulse passes the copper wire at time t 1 = 0, and at a later time t 2 you observe new non-zero electric and magnetic fields at your location. What is t 2 ? (give a numerical answer.) numerical answer.) (No Response) 4.00e-08 s (c) What is the direction of the new electric field at your location? -z -z (d) What is the direction of the new magnetic field at your location? +y +y (e) What is the direction of the new electric field at your friend's location? none (zero magnitude) none (zero magnitude) (f) What is the direction of the new magnetic field at your friend's location? none (zero magnitude) none (zero magnitude) ...
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This note was uploaded on 09/21/2010 for the course PY 005 taught by Professor Mattewk. during the Spring '10 term at N.C. State.

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