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

$A$ plane electromagnetic wave with a frequency of $30 \text{ MHz}$ travels in free space. At a particular point in space and time,the electric field is $6 \text{ V/m}$. The magnetic field at this point will be $x \times 10^{-8} \text{ T}$. The value of $x$ 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

An electric charge oscillating harmonically with frequency $750 kHz$ produces electromagnetic waves of frequency. (Speed of light in vacuum is $3 \times 10^8 \ m/s$) (in $kHz$)

$A$ plane electromagnetic wave is moving in free space with velocity $c = 3 \times 10^8 \ m/s$ and its electric field is given as $\vec{E} = 54 \sin(kz - \omega t) \hat{j} \ V/m$, where $\hat{j}$ is the unit vector along the $y$-axis. The magnetic field vector $\vec{B}$ of the wave is:

The electric field in an electromagnetic wave is given by $\overrightarrow{E} = \hat{i} 40 \cos \omega(t - \frac{z}{c}) \text{ N/C}$. The magnetic field induction of this wave is (in $SI$ units):