Solved Problem for Electromagnetic Waves | PHYS 4D, Quizzes of Physics

Download Solved Problem for Electromagnetic Waves | PHYS 4D and more Quizzes Physics in PDF only on Docsity! Problem 1 A laser pointer delivers 0.10 mW average power in a beam 0.90 mm in diameter. Find (a) the average intensity, (b) the peak electric field, (c) the peak magnetic field. Solution:  S P 1 4 d 2 157 W/m2. 344)/(2/22 00000  cSSScE  V/m  B0 E0 c1.15  T . Problem 2 At 1.5 km from the transmitter, the peak electric field of a radio wave is 350 mV/m. (a) What is the transmitter’s power output, assuming it broadcasts uniformly in all directions? (b) What is the peak electric field 10 km from the transmitter? Solution: (a)  P 4r 2 (E0 2 20c) 4.59 kW (b) Since  r 2E0 2 const ,  E0 ' (r r')E0 52.5 mV/m at a distance of 10 km. Problem 3 The average intensity of a particular TV station’s signal is  1.0 10 13 W/m2 when it arrives at 33-cm –diameter satellite TV antenna. (a) Calculate a total energy received by the antenna during 6 hours of viewing this station’s programs. (b) What are the amplitudes of E and B fields of the EM wave? Solution: This is Problem 53 in Giancoli textbook. (a) .108.1 4 1 102 JdtSE   (b) ./107.8)/(2/22 600000 mVcSSScE   .109.2/ 1400 TcEB 