20.08.2019

MASSACHUSETTS COMPANY OF TECHNOLOGY Department of Electrical Executive and Pc Science Difficulty Set No . 2 six. 632 Electromagnetic Wave Theory Issued: 02/15/07 R Spring Term 2007 Due: 02/22/07 R -----------------------------------------------------------------------------Reading assignment: Section 3. two J. A. Kong, " Electromagnetic Trend Theory” Difficulty P2. 1 (a) The complex permittivity for lower part round beef is about = 40(1 + i0. 3) o in the operating consistency (2. 5 GHz) of the microwave oven. What is the penetration depth? (b) Calculate damage tangents and skin depths for ocean water in frequencies 62 Hz and 10 MHz. Sea water can be seen as a conductivity σ = four mho/m, permittivity = eighty 0, and permeability µ = µo at all those frequencies. (c) A 100-Hz electromagnetic say is propagating down into the ocean water with an electric ﬁeld intensity Elizabeth of 1 V/m just beneath the ocean surface. What is the power of Electronic at a depth of 100 m? What are the time-average Poynting's power densities just beneath the area and at a depth of 100 m? Problem P2. 2 Superconductivity was ﬁrst observed simply by Kamerlingh Onnes in 1911. In 1933 Meissner and Ochsenfeld discovered that superconducting metals cannot be permeated by permanent magnet ﬁelds. Permanent magnetic ﬁelds happen to be expelled from a normal steel when it is cooled down to the superconducting state. The macroscopic theory of superconductivity was developed by simply London and London in 1935 accompanied by the microscopic theory of Bardeen, Cooper and Schrieﬀer in 1957. A simple type of superconductivity requires an electron plasma using a very high electron density N. (a) Show that the penetration depth of a plasma with very large D takes the shape dp sama dengan m D e2 µ0

(b) Enabling N sama dengan 7 × 1028 m−3, calculate dp. (c) Assess the above effect with the epidermis depth of your good conductor. Explain how come a very gradually varying permanent magnetic ﬁeld can penetrate a fantastic conductor but is not a superconductor. Problem P2. 3 A great electron plasma becomes anisotropic when an exterior dc...