The speed of electromagnetic wave in vacuum depends upon the source of radiation

A plane electromagnetic wave travels in a medium of relative permeability $1.61$ and relative permittivity $6.44$. If magnitude of magnetic intensity is $4.5 \times 10^{-2} \;Am ^{-1}$ at a point, what will be the approximate magnitude of electric field intensity at that point$?$

(Given : permeability of free space $\mu_{0}=4 \pi \times 10^{-7}\;NA ^{-2}$, speed of light in vacuum $c =3 \times 10^{8} \;ms ^{-1}$ )

Light with an average flux of $20\, W / cm ^{2}$ falls on a non-reflecting surface at normal incidence having surface area $20\, cm ^{2} .$ The energy recelved by the surface during time span of $1$ minute is $............J$

The electric field part of an electromagnetic wave in a medium is represented by

$E_x=0, E_y=2.5 \frac{N}{C}\, cos\,\left[ {\left( {2\pi \;\times\;{{10}^6}\;\frac{{rad}}{s}\;\;} \right)t - \left( {\pi \;\times\;{{10}^{ - 2}}\;\frac{{rad}}{m}} \right)x} \right]$,and  $ E_z=0$ . The wave is

An electric charge $+ q$ moves with velocity $\overrightarrow V  = 3\hat i + 4\hat j + \hat k$ in an electromagnetic field given by :  $\overrightarrow E  = 3\hat i + \hat j + 2\hat k$ and $\overrightarrow B  = \hat i + \hat j - 3\hat k$. The $y-$ component of the force experienced by $+ q$ is :-

The electric field component of an electromagnetic wave in vaccum is given as $\vec E = 3\cos \,\left( {1.8y + 5.4 \times {{10}^8}\,t} \right)\hat i$ Its direction of propagation and wavelength is