6.27 A Hertzian dipole is a short conducting wire carrying an approximately constant current over its length l. If such a dipole is placed along the z axis with its

midpoint at the origin and if the current flowing through it is i(t) = Io cos wt, find the following: (a) The retarded vector potential A(R,0,0) at an observation point Q(R, 0,0) in a spherical coordinate system. (b) The magnetic field phasor H(R, 0,0).Assume I to be sufficiently small so that the observation point is approximately equidistant to all points on the dipole; that is,assume R'= R.