A0.5-mhz antenna carried by an airplane flying over the ocean surface generates a wave that approaches the water surface in the form of a normally incident plane wave with an electric-field amplitude of 3000 v/m. sea water is characterized by and the plane is trying to communicate a message to a submarine submerged at a depth d below the water surface. if the submarine’s receiver requires a minimum signal amplitude of 0.01 what is the maximum depth d to which successful communication is still possible?