A plane electromagnetic wave propagating in free space is incident normally on a large slab of loss-less, non-magnetic, dielectric material with \in>\in_0. Maxima and minima are observed when the electric field is measured in front of the slab. The maximum electric field found to be 5 times the minimum field. The intrinsic impedance of the medium should be_____.
(a) 120π Ω
(b) 60π Ω
(c) 600π Ω
(d) 24π Ω
Ans :- (d)
Explanation
SWR=\frac{E_{max}}{E_{min}} \therefore s=5 \therefore 5=\frac{1+\left|\Gamma\right|}{1-\left|\Gamma\right|}\;\;\left|\Gamma\right|=\frac23 \therefore\Gamma=-\frac23 -\frac23=\frac{\eta_2-120\pi}{\eta+120\pi} \eta_2=24\pi