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?

Suppose that intensity of a laser is $\left(\frac{315}{\pi}\right)\, W / m ^{2} .$ The $rms$ electric field, in units of $V / m$ associated with this source is close to the nearest integer is $\left(\epsilon_{0}=8.86 \times 10^{-12} C ^{2} Nm ^{-2} ; c =3 \times 10^{8} ms ^{-1}\right)$

The velocity of certain ions that pass undeflected through crossed electric field $E = 7.7\,k\,V /m$ and magnetic field $B = 0.14\,T$ is…..$km/s$

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  $\mathrm{c}=3 \times 10^{8}\; \mathrm{ms}^{-1})$

Show that the radiation pressure exerted by an $EM$ wave of intensity $I$ on a surface kept in vacuum is $\frac{I}{c}$.