A monochromatic signal at the frequency of 2GHz propagates in a lossless coaxial cable where you have a dielectric with relative permittivity of εr=4 between the inner and outer conductors with radii of 1 and 2 mm, respectively. Find (a) the characteristic impedance; (b) the propagation constant β; (c) the phase velocity of the signal vp; (d) the "guided" wavelength λg of the wave in the coaxial cable.