Light wave is travelling along y-direction. If the corresponding $\vec E$ vector at any time is along the $x-$axis, the direction of $\vec B$ vector at that time is along

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

The vector $\vec E$ and $\vec B$ of an electromagnetic wave in vacuum are

The energy of an electromagnetic wave contained in a small volume oscillates with

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.

For a transparent medium relative permeablity and permittlivity, $\mu_{\mathrm{r}}$ and $\epsilon_{\mathrm{r}}$ are $1.0$ and $1.44$ respectively. The velocity of light in this medium would be,