finding expression for instantaneous Electric field


by zak8000
Tags: electric, expression, field, instantaneous
zak8000
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#1
Jun18-11, 12:26 AM
P: 73
1. The problem statement, all variables and given/known data
hi i have been given the following electric field phasor E=(z(5)+x(10))e-jpi(y) mV/m

Mr=100
er=3

2. Relevant equations



3. The attempt at a solution
i have been able to deduce from the results above that wave is travelling in positive y direction.

intrinsic impedance = 2176 ohms from n=sqrt(M/e)
wave velocity =17x10^6 ms-1 from v=1/sqrt(M*e)
wavelength =2pi/k=2
angular frequency=kv=17pi*10^6

so to find instanteous expression for E it should be of the form:

E(y,t)=Acos(wt-ky)
E(y,t)=(z(5)+x(10))cos(17pi*10^6*t-pi*y) is this correct ? i am just confused because there are two component is the amplitude. so is this valid?
and also for the corresponding magnetic field
H=(x(5/2176)-z(10/2176))e-jpi(y) mA/m

H(y,t)=(x(5/2176)-z(10/2176))cos(17pi*10^6*t-pi*y) is this an correct expression for the corresponing magnetic field in instantaneous form?
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