A uniform plane wave in air impinge at 45° angle on a lossless dielectric material with dielectric constant ε_r. The transmitted wave propagates at a 30° direction with respect to the normal. The value of ϵ_r is:

1.5

\(\sqrt {1.5} \)

√2

A uniform plane wave in air impinge at 45° angle on a lossless dielectric material with dielectric constant εr. The transmitted wave propagates at a 30° direction with respect to the normal. The value of ϵr is: