 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India Electromagnetic Radiation

 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India Light – particle ?

 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India Light – particle or wave? A closer look Fringes

 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India Light – particle or wave? Not possible to explain Fringes if light is particles Light is an Electromagnetic Waves

 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India Electric Field Coulumb’s Law

 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India Electric Field Coulumb’s Law Implies instaneous propagation of information Not fully correct

 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India J.C. Maxwell in 1880s Proposed a modification Signal cannot propagate at speed faster than c Unifies Electricity and Magnetism - Electromagnitism

 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India Electric Field Electric field at time t is determined by the position of the charge at some earlier time t the retarded time retarded position

 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India Electric and Magnetic Fields retarded position

 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India Electric Field Electromagnetic radiation Only emitted by accelerating charged particles

 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India Electromagnetic radiation Only emitted by accelerating charged particles Can influence charged particles at large distances Carried energy to infinity

 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India Simplifiying assumptions L L << r Velocity and acceleration are sufficiently low

 Somnath Bharadwaj and Pratik Khastgir, Department of Physics and Meteorology, IIT Kharagpur, India Electromagnetic Radiation