A velocity selector consists of electric field $\overrightarrow{ E }= E \hat{ k }$ and magnetic field $\overrightarrow{ B }= B \hat{ j }$ with $B =12 mT$.

The value $E$ required for an electron of energy $728 eV$ moving along the positive $x$-axis to pass undeflected is:

(Given, , ass of electron $=9.1 \times 10^{-31} kg$ )

A plane electromagnetic wave of wave intensity $6\, W/ m^2$ strikes a small mirror area $40 cm^2$, held perpendicular to the approaching wave. The momentum transferred by the wave to the mirror each second will be

In an electromagnetic wave, the amplitude of electric field is $1 V/m.$  the frequency of wave is $5 \times {10^{14}}\,Hz$. The wave is propagating along $z-$ axis. The average energy density of electric field, in $Joule/m^3$, will be

If $c $ is the speed of electromagnetic waves in vacuum, its speed in a medium of dielectric constant $K$ and relative permeability ${\mu _r}$ is

If electric field intensity of a uniform plane electro magnetic wave is given as

$E =-301.6 \sin ( kz -\omega t ) \hat{a}_{ x }+452.4 \sin ( kz -\omega t )$ $\hat{a}_{y} \frac{V}{m}$

Then, magnetic intensity $H$ of this wave in $Am ^{-1}$ will be

[Given: Speed of light in vacuum $c =3 \times 10^{8} ms ^{-1}$, permeability of vacuum $\mu_{0}=4 \pi \times 10^{-7} NA ^{-2}$ ]

An electromagnetic wave travels along $z-$axis. Which of the following pairs of space and time varying fields would generate such a wave