1. What is the condition for a medium to be a perfect dielectric? How do the characteris- tics of wave propagation in a perfect dielectric medium differ from those of wave propagation in free space?
2. What is the criterion for a material to be an imperfect dielectric? What is the significant feature of wave propagation in an imperfect dielectric as compared to that in a perfect dielectric?
3. Give two examples of materials that behave as good dielectrics for frequencies down to almost zero.
4. What is the criterion for a material to be a good conductor?
5. Give two examples of materials that behave as good conductors for frequencies of up to several gigahertz.