The electric field associated with an em wave in vacuum is given by $\vec{E}=\hat{i} 40 \cos \left(k z-6 \times 10^{8} t\right)$ where $E, x$ and $t$ are in $volt/m,$ meter and seconds respectively. The value of wave vector $k$ is....$ m^{-1}$

A plane electromagnetic wave of frequency $28 \,MHz$ travels in free space along the positive $x$-direction. At a particular point in space and time, electric field is $9.3 \,V / m$ along positive $y$-direction. The magnetic field (in $T$ ) at that point is

Two electrons are moving with same speed $v$. One electron enters a region of uniform electric field while the other enters a region of uniform magnetic field. Then after some time if the de-broglie wavelength of the two are ${\lambda _1}$ and ${\lambda _2}$  then

What is radiation pressure ? 

Even though an electric field $E$ exerts a force $qE$ on a charged particle yet the electric field of an $EM$ wave does not contribute to the radiation pressure (but transfers energy). Explain.

The electric field part of an electromagnetic wave in a medium is represented by $E_x = 0\,;$

${E_y} = 2.5\,\frac{N}{C}\,\,\cos \,\left[ {\left( {2\pi \, \times \,{{10}^6}\,\frac{{rad}}{m}} \right)t - \left( {\pi  \times {{10}^{ - 2}}\frac{{rad}}{s}} \right)x} \right];$

$E_z = 0$. The wave is