Consider two sources J, and M, radiating in an unbounded medium of constitutive parameters & and 4. Included within the medium is an imaginary volume VI enclosed by an imaginary surface S. The fields everywhere are E, and H. The volume Vi is now replaced by an obstacle of constitutive parameters e, and fly. The sources continue radiating. It is desired to determine the scattered fields E, and H, outside the obstacle and the transmitted fields E, and H, within the obstacle. Develop the equivalent problem describing the steps and giving reference to the appropriate theorem. M EH E.H