Which scientist discarded postulate of ether?
What is force exerted on surface having area of $10\, cm^2$ due to radiation of Sun ?
The electric field of a plane electromagnetic wave varies with time of amplitude $2\, Vm^{-1}$ propagating along $z$ -axis. The average energy density of the magnetic field (in $J\, m^{-3}$) is
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 $c =3 \times 10^{8} \;ms ^{-1}$ )
Electromagnetic waves travel in a medium which has relative permeability $1.3$ and relative permittivity $2.14$. Then the speed of the electromagnetic wave in the medium will be
An electromagnetic wave travelling in the $x-$ direction has frequency of $2 \times 10^{14}\,Hz$ and electric field amplitude of $27\,Vm^{-1}$ . From the options given below, which one describes the magnetic field for this wave ?