The speed of an electromagnetic wave in a vacuum depends upon the source of radiation.

When an $EM$ wave propagates through a vacuum,then:

The pressure exerted by an electromagnetic wave of intensity $I \ (W/m^2)$ on a non-reflecting surface is [$c$ is the velocity of light].

$A$ plane electromagnetic wave propagating in $x$-direction is described by $E_{y} = (200 \ Vm^{-1}) \sin [1.5 \times 10^7 t - 0.05 \ x]$. The intensity of the wave is: (Use $\epsilon_0 = 8.85 \times 10^{-12} \ C^2 \ N^{-1} \ m^{-2}$) (in $Wm^{-2}$)

$A$ laser beam has intensity $2.1 \times 10^{15} \ W/m^2$. The amplitude of the magnetic field in the beam is approximately: (in $T$)

Which of the following pairs of components can produce a plane electromagnetic wave propagating in a direction such that the electric field $\vec{E} = (E_x\hat{i} + E_y\hat{j} + E_z\hat{k})$ and magnetic field $\vec{B} = (B_x\hat{i} + B_y\hat{j} + B_z\hat{k})$ vary with position and time?