The electric field of a plane polarized electromagnetic wave in free space at time $t = 0$ is given by an expression
$\vec E(x,y) = 10\hat j\, cos[(6x + 8z)]$
The magnetic field $\vec B (x,z, t)$ is given by : ($c$ is the velocity of light)
$\frac{1}{c}\left( {6\hat k + 8\hat i} \right)\,\cos \,\left[ {\left( {6x - 8z + 10ct} \right)} \right]$
$\frac{1}{c}\left( {6\hat k - 8\hat i} \right)\,\cos \,\left[ {\left( {6x + 8z - 10ct} \right)} \right]$
$\frac{1}{c}\left( {6\hat k + 8\hat i} \right)\,\cos \,\left[ {\left( {6x + 8z - 10ct} \right)} \right]$
$\frac{1}{c}\left( {6\hat k - 8\hat i} \right)\,\cos \,\left[ {\left( {6x + 8z + 10ct} \right)} \right]$
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
The average value of electric energy density in an electromagnetic wave is :
A plane electromagnetic wave is incident on a material surface. If the wave delivers momentum $p$ and energy $E$, then
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.
The monoenergetic beam of electrons moving along $+ y$ direction enters a region of uniform electric and magnetic fields. If the beam goes straight undeflected, then fields $B$ and $E$ are directed respectively along