1. Write a single exact expression for the attenuation constant α for a plane wave propagating in a material that may or may not be lossy. Give your answer explicitly in terms of the frequency f and material parameters µ, ǫ, and σ.
2. It is found that propagation through 2.3 mm of some material results reduces the magnitude of the electric ﬁeld intensity to one-half of it’s original value. What is the skin depth of this material?