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

The electric field component of a monochromatic radiation is given by

$\vec E = 2{E_0}\,\hat i\,\cos\, kz\,\cos\, \omega t$

Its magnetic field $\vec B$ is then given by

Which of the following statement is false for the properties of electromagnetic waves ?

For a plane electromagnetic wave, the magnetic field at a point $x$ and time $t$ is

$\overrightarrow{ B }( x , t )=\left[1.2 \times 10^{-7} \sin \left(0.5 \times 10^{3} x +1.5 \times 10^{11} t \right) \hat{ k }\right] T$

The instantaneous electric field $\overrightarrow{ E }$ corresponding to $\overrightarrow{ B }$ is : (speed of light $\left.c=3 \times 10^{8} ms ^{-1}\right)$

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

A long straight wire of resistance $R$, radius $a $ and length $ l$ carries a constant current $ I.$ The Poynting vector for the wire will be