Generation of Radio Waves Accelerating charges produce electromagnetic waves
Generation of Radio Waves E + + + - - - + - - + - - - + + + Accelerating charges produce electromagnetic waves
米C2k Why are cell phone antennas so short?
Why are cell phone antennas so short?
Interrelated electric and magnetic fields traveling through space Electromagnetic waves travel through empty space All electromagnetic radiation travels at c=3 x 108 m/s in vacuum-the cosmic speed limit!
Electromagnetic Radiation • Interrelated electric and magnetic fields traveling through space • Electromagnetic waves travel through empty space All electromagnetic radiation travels at c=3 x 108 m/s in vacuum – the cosmic speed limit!
For plane electromagnetic waves travel in x direction: By Maxwell's equations: E aB Wavefronts Ray (a) Bx 8t aB E -8 Bxc 8t E () 82E B Electric- -Magnetic 8t2 component component
For plane electromagnetic waves travel in x direction: By Maxwell’s equations:
Compared with the wave equation of mechanical waves Let: E=E sin(kx-@t) B=B sin(kx-@t) OE aB m Bx 8t B Hm
Compared with the wave equation of mechanical waves Let: