An electromagnetic wave of frequency $3 \, GHz$ enters a dielectric medium of relative electric permittivity $2.25$ from vacuum. The wavelength of this wave in that medium will be $....... \times 10^{-2} \, cm$.

$A$ point source of $100\,W$ emits light with $5\%$ efficiency. At a distance of $5\,m$ from the source,the intensity produced by the electric field component is:

Even though an electric field $E$ exerts a force $qE$ on a charged particle, the electric field of an $EM$ wave does not contribute to the radiation pressure (but transfers energy). Explain.

Select the incorrect statement regarding electromagnetic waves.

An electromagnetic wave of frequency $3.0 \ MHz$ passes from vacuum into a non-magnetic medium with permittivity $\epsilon = 16 \epsilon_0$,where $\epsilon_0$ is the free space permittivity. The change in wavelength is

The electric field of an electromagnetic wave travelling through a medium is given by $\overline{E}(x,t) = 25 \sin(2.0 \times 10^{15}t - 10^{7}x)\hat{n}$. The refractive index of the medium is . . . . . . . (All given measurements are in $SI$ units)