Electromechanical Dynamics (Part 1).0032

Electromechanical Dynamics (Part 1).0032 - conductor the...

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Electromagnetic Theory for (1.1.21) and (1.1.22) enclose a volume V, whereas those of (1.1.20) and (1.1.23) are enclosed by a contour C. Equations 1.1.20 to 1.1.23 are valid even when the contours and surfaces are deforming, as demonstrated in Appendix B. Note that in (1.1.23) the electric field intensity is written as E', and it is this value that would be measured by an observer attached to the deforming contour at the point in question. As demonstrated in Section B.4. 1, when E' = E x (v x B), where v is the local velocity of the contour, (1.1.23) results from (1.1.5). More is said about the relation between quantities measured by observers in relative motion in Chapter 6. In describing magnetic field systems, in addition to (1.1.20) to (1.1.23), we need constituent relations such as (1.1.8) and (1.1.9). We must keep in mind that these constituent relations are defined for stationary media. When there is motion, these equations still hold, but only for an observer moving with the medium. Thus we know that a perfect conductor can support no electric field intensity E'. When the contour of (1.1.23) is fixed to a perfect
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Unformatted text preview: conductor, the contribution to the contour integral from that portion in the conductor is zero, whether the conductor is moving or not. This is because E' is the quantity measured by an observer moving with the contour (conductor). 1.1.2b Electric Field Systems The integral forms of (1.1.11) to (1.1.15) are SE. dl = 0, (1.1.24) sD .nda = pf dV, (1.1.25) Jf nda = p dV, (1.1.26) H' -di = J1-n da + D f n da. (1.1.27) These equations are valid for moving and deforming contours C, surfaces S, and volumes V (see Fig. 1.1.1). Equations 1.1.24 and 1.1.25 are the same as those used to find E and D in an electrostatics problem. The current density and magnetic field intensity have been written in (1.1.26) and (1.1.27) as J; and H' to indicate that they are the values that would be measured by an observer moving with the contour or surface at the point in question. It is shown in Section B.4.2 that 1.1.2 A-PDF Split DEMO : Purchase from www.A-PDF.com to remove the watermark...
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