The average value of electric energy density in an electromagnetic wave is :

The ratio of amplitude of magnetic field to the amplitude of electric field for an electromagnetic wave propagating in vacuum is equal to 

The magnetic field of a plane electromagnetic wave is given by

$\vec B\, = {B_0}\hat i\,[\cos \,(kz - \omega t)]\, + \,{B_1}\hat j\,\cos \,(kz - \omega t)$ where ${B_0} = 3 \times {10^{-5}}\,T$ and ${B_1} = 2 \times {10^{-6}}\,T$. The rms value of the force experienced by a stationary charge $Q = 10^{-4} \,C$ at $z = 0$ is closet to

Consider an electromagnetic wave propagating in vacuum . Choose the correct statement

Ratio of electric field and magnetic field gives which physical quantity ? 

If ${\varepsilon _0}$ and ${\mu _0}$ are respectively, the electric permittivity and the magnetic permeability of free space. $\varepsilon $ and $\mu $ the corresponding quantities in a medium, the refractive index of the medium is