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

The magnetic field of a plane electromagnetic wave is given by $\vec B = B_0 \hat i \cos(kz - \omega t) + B_1 \hat j \cos(kz - \omega t)$,where $B_0 = 3 \times 10^{-5} \, T$ and $B_1 = 2 \times 10^{-6} \, T$. The rms value of the force experienced by a stationary charge $Q = 10^{-4} \, C$ at $z = 0$ is closest to:

The solar radiation is:

$A$ plane electromagnetic wave of frequency $25\; GHz$ is propagating in vacuum along the $z$-direction. At a particular point in space and time,the magnetic field is given by $\overrightarrow{B} = 5 \times 10^{-8} \hat{j}\; T$. The corresponding electric field $\overrightarrow{E}$ is (speed of light $c = 3 \times 10^{8}\; m/s$):

$A$ point source of electromagnetic radiation has an average power output of $800 \, W$. The maximum value of the electric field at a distance $4.0 \, m$ from the source is .... $V/m$.

The electric field for a plane electromagnetic wave travelling in the $+y$ direction is shown in the figure. Consider a point where the electric field is in the $+z$ direction. The magnetic field $\vec B$ is