An electromagnetic wave travels along $z-$axis. Which of the following pairs of space and time varying fields would generate such a wave

In an electromagnetic wave in free space the root mean square value of the electric field is $E_{rms} = 6\, V m^{-1}$ The peak value of the magnetic field is

Energy stored in electromagnetic oscillations is in the form of

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

The magnetic field vector of an electromagnetic wave is given by ${B}={B}_{o} \frac{\hat{{i}}+\hat{{j}}}{\sqrt{2}} \cos ({kz}-\omega {t})$; where $\hat{i}, \hat{j}$ represents unit vector along ${x}$ and ${y}$-axis respectively. At $t=0\, {s}$, two electric charges $q_{1}$ of $4\, \pi$ coulomb and ${q}_{2}$ of $2 \,\pi$ coulomb located at $\left(0,0, \frac{\pi}{{k}}\right)$ and $\left(0,0, \frac{3 \pi}{{k}}\right)$, respectively, have the same velocity of $0.5 \,{c} \hat{{i}}$, (where ${c}$ is the velocity of light). The ratio of the force acting on charge ${q}_{1}$ to ${q}_{2}$ is :-