A radar antenna transmits 50 kW at 10 GHz. Assume transmission is in a narrow beam, 1 m2 in area, and that within the beam, waves are plane waves. The wave is re?ected from an aircraft but only 1 % of the power propagates in the direction of the antenna. If the airplane is at a distance of 100 km, calculate the total power received by the antenna. Assume permittivity and permeability of free space.