For an electromagnetic wave travelling in free space,the relation between average energy densities due to electric $(U_{e})$ and magnetic $(U_{m})$ fields is

The electromagnetic waves travel in a medium at a speed of $2.0 \times 10^{8} \ m/s$. The relative permeability of the medium is $1.0$. The relative permittivity of the medium will be (in $.25$)

$A$ $27\, mW$ laser beam has a cross-sectional area of $10\, mm^2$. The magnitude of the maximum electric field in this electromagnetic wave is given by: $........\, kV/m$. [Given permittivity of free space $\epsilon_0 = 9 \times 10^{-12}\, SI\, units$, speed of light $c = 3 \times 10^8\, m/s$]

$A$ wave is propagating in a medium of electric dielectric constant $2$ and relative magnetic permeability $50$. The wave impedance of such a medium is.....$ \Omega$

An electromagnetic wave of frequency $5\, GHz$ is travelling in a medium whose relative electric permittivity and relative magnetic permeability both are $2$. Its velocity in this medium is $\times 10^{7}\, m/s$.

$A$ radio can tune into any station in the $6 \text{ MHz}$ to $12 \text{ MHz}$ band. What is the corresponding wavelength band? ( $c = 3 \times 10^{8} \text{ m/s}$ )