The electromagnetic waves travel with a velocity

$A$ point source of electromagnetic radiation has an average output power of $800 \, W$. What is the maximum value of the electric field at a distance of $3.5 \, m$ from the source in $V/m$?

$A$ light bulb emits power of $800 \, W$. What is the maximum value of the electric field at a distance of $3.5 \, m$ from the bulb in $V/m$?

An electromagnetic wave travelling in a lossless dielectric medium having a dielectric constant $\epsilon_r = 9$, has the electric field, $E_x = E_0 \sin (kz - 2\pi \times 10^6 t) \text{ Vm}^{-1}$ where $E_0$ is the amplitude and $k$ is the wave vector. Among the following options, the incorrect choice is :

In a plane electromagnetic wave,the maximum value of the electric field component is $4.4 \ Vm^{-1}$. The intensity of the wave is nearly (in $mW \ m^{-2}$)

Electromagnetic waves are transverse in nature is evident by