The $$\overrightarrow H $$ field (in A/m) of a plane wave propagating in free space is given by $$$\overrightarrow H = \widehat x{{5\sqrt 3 } \over {{\eta _0}}}\cos \left( {\omega \,t - \beta \,z} \right) + \widehat y{5 \over {{\eta _0}}}\sin \left( {\omega \,t - \beta \,z + {\pi \over 2}} \right)$$$

The time average power flow density in Watts is

A medium of relative permittivityb $${\varepsilon _r} = 2$$ forms an interface with free-space. A point source of electromagnetic energy is located in the medium at a depth of $$1$$ meter from the interface. Due to the total internal reflection, the transmitted beam has a circular cross-section over the interface. The area of the beam cross-section at the interface is given by

A medium is divided into regions $${\rm I}$$ and $${\rm I}$$$${\rm I}$$ about $$x = 0$$ plane, as shown in the Fig. below. An electromagnetic wave with electric field $${\overrightarrow E _1} = 4{\widehat a_x} + 3{\widehat a_y} + 5{\widehat a_z}$$ is incident normally on the interface form region-$${\rm I}$$ . The electric field $${E_2}$$ in region-$${\rm I}$$$${\rm I}$$ at the interface is

When a plane wave traveling in free-space is incident normally on a medium having $${\varepsilon _r} = 4.0,$$ the fraction of power transmitted into the medium is given by