An electromagnetic wave with frequency $\omega $ and wavelength $\lambda $ travels in the $+y$ direction. Its magnetic field is along $+x$ axis. The vector equation for the associated electric field (of amplitude $E_0$) is
$\vec E = {E_{0\,}}\,\cos \left( {\omega t - \frac{{2\pi }}{\lambda }y} \right)\hat x$
$\vec E = -{E_{0\,}}\,\cos \left( {\omega t + \frac{{2\pi }}{\lambda }y} \right)\hat x$
$\vec E = -{E_{0\,}}\,\cos \left( {\omega t + \frac{{2\pi }}{\lambda }y} \right)\hat z$
$\vec E = {E_{0\,}}\,\cos \left( {\omega t - \frac{{2\pi }}{\lambda }y} \right)\hat z$
The electric field of plane electromagnetic wave of amplitude $2\,V/m$ varies with time, propagating along $z-$ axis. The average energy density of magnetic field (in $J/m^3$ ) is
The oscillating electric and magnetic vectors of an electromagnetic wave are oriented along
The electromagnetic waves travel with a velocity
A radiation is emitted by $1000\, W$ bulb and it generates an electric field and magnetic field at $P$, placed at a distance of $2\, m$. The efficiency of the bulb is $1.25 \%$. The value of peak electric field at $P$ is $x \times 10^{-1} \,V / m$. Value of $x$ is. (Rounded-off to the nearest integer)
[Take $\varepsilon_{0}=8.85 \times 10^{-12} C ^{2} N ^{-1} m ^{-2}, c =3 \times 10^{8}$ $ms ^{-1}$ ]
A radar sends an electromagnetic signal of electric field $\left( E _{0}\right)=2.25\,V / m$ and magnetic field $\left( B _{0}\right)=1.5 \times 10^{-8}\,T$ which strikes a target on line of sight at a distance of $3\,km$ in a medium After that, a pail of signal $(echo)$ reflects back towards the radar vitli same velocity and by same path. If the signal was transmitted at time $t_{0}$ from radar. then after how much time (in $\times 10^{-5}\,s$) echo will reach to the radar?