In an $E.M.$ wave,the average energy density is associated with

$A$ plane electromagnetic wave of frequency $50 \ MHz$ travels in free space. If the average energy densities in the electric field and magnetic field are $K_{E}$ and $K_{B}$ respectively,then the correct option in the following is

Energy stored in electromagnetic oscillations is in the form of

$A$ plane electromagnetic wave travels in free space along the $x$-direction. The electric field component of the wave at a particular point of space and time is $E = 6 \; Vm^{-1}$ along the $y$-direction. Its corresponding magnetic field component, $B$, would be:

The electric fields of two plane electromagnetic waves in vacuum are given by $\overrightarrow{E}_{1}=E_{0} \hat{j} \cos (\omega t-kx)$ and $\overrightarrow{E}_{2}=E_{0} \hat{k} \cos (\omega t-ky)$. At $t=0$,a particle of charge $q$ is at the origin with a velocity $\overrightarrow{v}=0.8 c \hat{j}$ ($c$ is the speed of light in vacuum). The instantaneous force experienced by the particle is:

If $c$ is the speed of electromagnetic waves in vacuum,its speed in a medium of dielectric constant $K$ and relative permeability $\mu_r$ is