An electromagnetic wave of intensity $50\,Wm^{-2}$ enters in a medium of refractive index $’ n’$ without any loss . The ratio of the magnitudes of electric fields, and the ratio of the magnitudes of magnetic fields of the wave before and after entering into the medium are respectively. Given by
$\left( {\frac{1}{{\sqrt n }},\frac{1}{{\sqrt n }}} \right)$
$\left( {\sqrt n ,\sqrt n } \right)$
$\left( {\frac{1}{{\sqrt n }},\sqrt n } \right)$
$\,\left( {\sqrt n ,\frac{1}{{\sqrt n }}} \right)$
The average value of electric energy density in an electromagnetic wave is :
In an electromagnetic wave, the amplitude of electric field is $1 V/m.$ the frequency of wave is $5 \times {10^{14}}\,Hz$. The wave is propagating along $z-$ axis. The average energy density of electric field, in $Joule/m^3$, will be
The oscillating electric and magnetic vectors of an electromagnetic wave are oriented along
A point source of electromagnetic radiation has an average power output of $800\,W$ . The maximum value of electric field at a distance $3.5\,m$ from the source will be.....$V/m$
If a source is transmitting electromagnetic wave of frequency $8.2 \times {10^6}Hz$, then wavelength of the electromagnetic waves transmitted from the source will be.....$m$