1. Give a short answer to the following questions:
(a) Define magnetization in terms of magnetic dipoles in matter.
What is its unit?
(b) What is Coulomb gauge? Use it to show the normal component
of the vector potential must be continuous at the boundary of two
materials.
(c) Use one of Maxwell's equations (which one?) to show that E
is perpendicular to the wave vector k in a plane electromagnetic
wave (easiest to use complex notation).