An electromagnetic wave of frequency $5\, GHz ,$ is travelling in a medium whose relative electric permittivity and relative magnetic permeability both are $2 .$ Its velocity in this medium is $\times 10^{7}\, m / s$
$12$
$18$
$15$
$20$
Light wave is travelling along y-direction. If the corresponding $\vec E$ vector at any time is along the $x-$axis, the direction of $\vec B$ vector at that time is along
An electric bulb is rated as $200 \,W$. What will be the peak magnetic field ($\times 10^{-8}\, T$) at $4\, m$ distance produced by the radiations coming from this bulb$?$ Consider this bulb as a point source with $3.5 \%$ efficiency.
A plane electromagnetic wave of frequency $25\; \mathrm{GHz}$ is propagating in vacuum along the $z-$direction. At a particular point in space and time, the magnetic field is given by $\overrightarrow{\mathrm{B}}=5 \times 10^{-8} \hat{\mathrm{j}}\; \mathrm{T}$. The corresponding electric field $\overrightarrow{\mathrm{E}}$ is (speed of light $\mathrm{c}=3 \times 10^{8}\; \mathrm{ms}^{-1})$
A plane electromagnetic wave of wave intensity $6\,W/m^2$ strike a small mirror of area $30\,cm^2$ , held perpendicular to a approching wave. The momentum transmitted in $kg\, m/s$ by the wave to the mirror each second will be
An electromagnetic wave of intensity $50\,Wm^{-2}$ enters in a medium of refractive index $’ n’$ without any loss . The ratio of the magnitudes of electric fields, and the ratio of the magnitudes of magnetic fields of the wave before and after entering into the medium are respectively. Given by