(a) The electric field of an electromagnetic wave propagating in free space is described by the equation E(z,t) = E0 [xsin(kz-wt) + ycos(kz-wt)] where x and y are unit vectors in the x- and y-direction, respectively. What is this wave's direction of propagation? What is the polarization of the wave? (b) State and prove the boundary conditions satisfied by the magnetic inten- sity H and the magnetic field B at the boundary between two media with different magnetic properties. (c) Show that tan T1/tan T2 = n1/n2 where T1 and T2 are incident and refraction angles.