4. In a perfect dielectric medium with the permeability of \(\mu\), there exists an electric field given as \(\mathbf{E} = E0cos(ωt - kz)ax, where E0 is the peak value, \(\omega\) is the frequency, k is a constant, and \(\hat{a}_x\) is the unit vector in x direction. What is the magnetic field (H) in the region?
(A)
(B)0
(C)
(D)
(E)None of the above
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統計: 尚無統計資料
統計: 尚無統計資料
詳解 (共 1 筆)
#7446303
所以看到電場方程式
立刻判斷wt-kz,朝向+z軸方向
然後利用電場方向和磁場方向外積可以得到傳播方向
x外積我們要求的方向會等於z方向
所以括號裡面的方向代表的是傳播方向
然後電場和磁場的比值直接記
為omegau/k
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