The velocity of electromagnetic radiation in a medium of permittivity $\varepsilon_0$ and permeability $\mu_0$ is given by:

$A$ point source of electromagnetic radiation has an average power output of $960 \,W$. The peak value of the electric field at a distance $400 \,cm$ from the source is (in $\,Vm^{-1}$)

If $\vec{E}$ and $\vec{K}$ represent the electric field and propagation vectors of electromagnetic $(EM)$ waves in a vacuum,respectively,then the magnetic field vector $\vec{B}$ is given by: (where $\omega$ is the angular frequency).

$A$ plane electromagnetic wave of frequency $25 \text{ MHz}$ propagates in vacuum along the positive $x$-direction. At a particular point in space and time,if the electric field is $6.3 \hat{j} \text{ Vm}^{-1}$,then the magnitude of the magnetic field of the wave at this point at the same time is:

The dimensions of $\frac{1}{{\mu _0}{\varepsilon _0}}$ are .......... .

In the propagation of electromagnetic waves,the angle between the direction of propagation and the plane of polarisation is......$^o$.