34CHAPTER OUTLINE34.1Maxwell’s Equations andHertz’s Discoveries34.2Plane ElectromagneticWaves34.3Energy Carried byElectromagnetic Waves34.4Momentum and RadiationPressure34.5Production ofElectromagnetic Waves byan Antenna34.6The Spectrum of Electromagnetic WavesElectromagnetic WavesANSWERS TO QUESTIONSQ34.1Radio waves move at the speed of light. They can travel aroundthe curved surface of the Earth, bouncing between the groundand the ionosphere, which has an altitude that is small whencompared to the radius of the Earth. The distance across thelower forty-eight states is approximately 5 000 km, requiring atransit time of 5101062××−m310mss8~. To go halfway around theEarth takes only 0.07 s. In other words, a speech can be heardon the other side of the world before it is heard at the back of alarge room.Q34.2The Sun’s angular speed in our sky is our rate of rotation,3602415°=°hh. In 8.3 minutes it moves west byθω==°FHGIKJt1518321hh60 minminbgaf.. . This is about four
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This note was uploaded on 12/14/2011 for the course PHY 203 taught by Professor Staff during the Fall '11 term at Indiana State University .