- #1
Maat
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Homework Statement
A uniform plane wave propagates in a non-dissipative medium in the positive z direction. The frequency of the wave is 20 MHz. A probe located at z = 0 measures the phase of the wave to be 98 degrees. An identical probe located at z = 2 m measures the phase to be -15 degrees. What is the relative permittivity (e/e0) of the medium.
Homework Equations
k = w*sqrt(u*e)
w = 2*pi*f
wt - kz = a constant
w is angle velocity, u is permeability, e is permittivity
The Attempt at a Solution
wt = phase angle
Phase angle = kz
K2 = -15/2 = -7.5
w = 2*pi*(20*10^6)
K2 = w*sqrt(u*e), solve for e (e2)
e2 = 2.83 * 10^-9 F/m
Now I'm stuck on how to get the other e since z = 0. I think this problem should be easy, but I'm not seeing something.