Ch 7 Radiation of Electromagnetic Waves 7.1, potentials of electromagnetic field gauge invariance 7.2 d' Alembert equation and retarded potential 7.3, electric dipole radiation 7.4 EM radiation from arbitrary motion charge7.1、potentials of electromagnetic field, gauge invariance 7.2、d’Alembert equation and retarded potential 7.3、electric dipole radiation 7.4、EM radiation from arbitrary motion charge Ch 7 Radiation of Electromagnetic Waves