A plane electromagnetic wave propagating in free space in incident normally on a large slab of loss-less, non-magnetic, dielectric material with $$\varepsilon > {\varepsilon _0}$$. Maxima and minima are observed when the electric field is measured in front of the slab. The maximum electric field is found to be $$5$$ times the minimum field. The intrinsic impedance of the medium should be

Medium $$1$$ has the electrical permittivity $${\varepsilon _1} = 1.5\,\,{\varepsilon _0}\,\,\,F/m$$ and occupies the region to left of $$x = 0$$ plane. Medium $$2$$ has the electrical permittivity $${\varepsilon _2} = 2.5\,\,{\varepsilon _0}\,\,\,F/m$$ and occupies the region to the right of $$x = 0$$ plane. If $${E_1}$$ in medium $$1$$ is $${E_1} = \left( {2\,{u_x} - 3\,{u_y} + 1\,{u_z}} \right)$$ volt/m, then $${E_2}$$ in medium $$2$$ is

A uniform plane wave traveling in air is incident on the plane boundary between air and another dielectric medium with $${\varepsilon _r} = 4$$. The reflection coefficient for the normal incidence, is

If the electric field intensity associated with a uniform plane electromagnetic wave traveling in a perfect dielectric medium is given by

$$E\left( {z,\,t} \right) = \,10\,\cos \left( {2\pi \times {{10}^7}\,\,t - 0.1\,\,\pi z} \right)\,$$ volt/m, the velocity of the traveling wave is