# test2 - ECE-3690, Second Exam March 26, 2008 100 minutes...

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ECE-3690, Second Exam March 26, 2008 100 minutes Closed Book (25 pts) 1. A transmitter, which is located just beneath the surface of the sea at z=0.0, is operating at f = 4 KHz. A receiver is positioned in the water at a vertical distance of 50 meters from the surface. For the seawater: ε = 81 ε 0 , μ = μ 0 and σ = 4 mho/m. (a) Is this a highly conducting medium? Explain. (b) What is the velocity of propagation in the seawater? (c) What is the penetration depth of the seawater? (d) Assuming that the receiver can detect the power density levels of larger than 0.1 m W/m 2 , calculate the minimum required power density level, at z=0.0, which must be generated by the transmitter. (15 pts) 2. The magnitude of the E fields at the interface of air and a dielectric plate are given by: |E 1 | = volts, |E 2 | = 2 volts. E 1 makes an angle of 45 o with the interface. |E1| |E2| 45 ! air " , μ # Assume there is a surface charge, ρ s = - 5 ε 0 , on the surface of the dielectric-plate in the air. Find angle θ .

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## This note was uploaded on 03/09/2010 for the course ECE 7600 taught by Professor Mobaserri during the Spring '10 term at Villanova.

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test2 - ECE-3690, Second Exam March 26, 2008 100 minutes...

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