PHY2061 R. D. Field Department of Physics chp38_14.doc University of Florida Energy Transport - Poynting Vector Electric and Magnetic Energy Density:For an electromagnetic plane waveEy(x,t) = E0sin(kx-ωt),Bz(x,t) = B0sin(kx-ωt),where B0= E0/c. The electric energy densityis given by uEEkxtE==−1212020022εεωsin ()and the magnetic energy densityis uBcEEuBE==1212120202202µµε, where I used E = cB. Thus, for light the electric and magnetic field energy densities are equaland the total energy densityis uuuEBEkxttotEB=+===−µεω02021sin (). Poynting Vector (rrrSEB=×10): The directionof the Poynting Vectoris the direction of energy
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