Ok, I am looking over stuff for an exam. I am a bit confused on something. When conductivity is zero, a medium is lossless. Zero conductivity means infinite resistance. For infinite resistance, no electrons will flow, but an electric field can propagate forever. A wire has high conductivity, so electrons can flow easily. I understand the difference between electrons and electric fields, but this seems counter-intuitive. Also, when conductivity is zero, the attenuation constant is not zero, though it is very small for small frequencies. Is everything here correct or am I overlooking something?