Add questions

_psets/6.md

+---
+title: Problem Set 6
+---
+
+## (8.1)
+
+{:.question}
+Find the electric field for an infinitesimal dipole radiator.
+
+## (8.2)
+
+{:.question}
+What is the magnitude of the Poynting vector at a distance of 1 km from an antenna radiating 1 kW of
+power, assuming that it is an isotropic radiator with a wavelength much less than 1 km? What is the
+peak electric field strength at that distance?
+
+## (8.3)
+
+{:.question}
+For what value of $$R_\text{load}$$ is the maximum power delivered to the load in Figure 8.3?
+
+## (8.4)
+
+{:.question}
+For an infinitesimal dipole antenna, what are the gain and the area, and what is their ratio?