1. Calculate the distance that a plane wave of frequency 1 GHz must travel in free space in order for its phase to be retarded by 90°. Repeat the calculation for propagation in a lossless dielectric with relative permittivity of nine.
2. Calculate the average power density and the magnetic field strength in a plane wave propagating in free space with peak electric field strength of 1 millivolt/meter. Repeat the calculation for propagation in a lossless dielectric with relative permittivity of four.