8.16 a 0.5 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 3,000 (v/m). seawater is characterized by r = 72, μr = 1, and σ = 4 (s/m). the plane is trying to communicate a message to a submarine submerged at a depth d belowthewater surface. if the submarine’s receiver requires a minimum signal amplitude of 0.01 (μv/m), what is the maximum depth d to which successful communication is still possible?

An external consultant recommends that a plant installs a bank of capacitors for power factor correction. this will reduce the peak electrical demand charges by an average of 93 kw every month. the plant current pays $13 per kw in peak demand charges. the capacitor bank will include 223 kw of fixed capacitors, and 183 of variable capacitors. the fixed capacitors cost $59 per kw, and the variable capacitors will cost $65 per kw. the consultant charges 21% of the equipment costs to install the capacitors. because this project will reduce the demand for the electric utility, they are prepared to provide a one-time rebate of $42 per kw of reduced demand. what is the simple payback period for this project (in years)?