An electromagnetic wave in vacuum has the electric and magnetic field $\vec E$ and $\vec B$ , which are always perpendicular to each other. The direction of polarization is given by $\vec X$ and that of wave propagation by $\vec k$ . Then
$\overrightarrow {X\;} $ $॥ $ $\vec B$ and $\overrightarrow {\;k} $ ॥$\overrightarrow {\;B} $ $\times $ $\vec E$
$\overrightarrow {X\;} $ $॥ $ $\vec E $ and $\overrightarrow {\;k} $ ॥$\overrightarrow {\;E} $ $\times $ $\vec B$
$\overrightarrow{X\;} $ $॥ $ $\vec B$ and $\overrightarrow {\;k} $ ॥$\overrightarrow {\;E} $ $\times $ $\vec B$
$\overrightarrow {X\;} $ $॥ $ $\vec E$ and $\overrightarrow {\;k} $ ॥$\overrightarrow {\;B} $ $\times $ $\vec E$
Electric field of plane electromagnetic wave propagating through a non-magnetic medium is given by ${E}=20 \cos \left(2 \times 10^{10} {t}-200 {x}\right) \,{V} / {m} .$ The dielectric constant of the medium is equal to :
(Take $\mu_{{r}}=1$ )
What physical quantity is the same for $X-$rays of wavelength $10^{-10} \;m ,$ $red$ light of wavelength $6800\; \mathring A$ and radiowaves of wavelength $500 \;m ?$
A $27\, mW$ lager beam has a cross -sectional area of $10\, mm^2$. The magnitude of the maximum electric field in this electromagnetic wave is given by:........$kV/m$ [Given permittivity of space ${ \in _0} = 9 \times {10^{ - 12}}\, SI\, units$, speed of light $c = 3 \times 10^8\, m/s$]
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 beam of light travelling along $X$-axis is described by the electric field $E _{ y }=900 \sin \omega( t - x / c )$. The ratio of electric force to magnetic force on a charge $q$ moving along $Y$-axis with a speed of $3 \times 10^{7}\,ms ^{-1}$ will be.
[Given speed of light $=3 \times 10^{8}\,ms ^{-1}$ ]