The magnetic field in a travelling electromagnetic wave has a peak value of $20\ n T$. The peak value of electric field strength is......$Vm^{-1}$

A plane $EM$ wave travelling along $z-$ direction is described$\vec E = {E_0}\,\sin \,(kz - \omega t)\hat i$ and $\vec B = {B_0}\,\sin \,(kz - \omega t)\hat j$. Show that

$(i)$ The average energy density of the wave is given by $U_{av} = \frac{1}{4}{ \in _0}E_0^2 + \frac{1}{4}.\frac{{B_0^2}}{{{\mu _0}}}$

$(ii)$ The time averaged intensity of the wave is given by  $ I_{av}= \frac{1}{2}c{ \in _0}E_0^2$ વડે આપવામાં આવે છે.

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

If a source of power $4\ kW$ produces $10^{20}$ photons/second , the radiation belongs to a part of the spectrum called

Electric field in a plane electromagnetic wave is given by ${E}=50 \sin \left(500 {x}-10 \times 10^{10} {t}\right) \,{V} / {m}$ The velocity of electromagnetic wave in this medium is :

(Given ${C}=$ speed of light in vacuum)

The amplitude of magnetic field in an electromagnetic wave propagating along $y$-axis is $6.0 \times 10^{-7}\,T$. The maximum value of electric field in the electromagnetic wave is: