2-1. In a certain homogeneous medium the group velocity as measured by the propagation time of a pulse is found to be proportional to the square root of the frequency (v8 = VAw where A is a constant) over a particular frequency range. It is assumed the medium is a nonmagnetic insulator. a. Determine the relationship between the phase and group velocities. b. Derive an expression for the relative dielectric constant of this medium.