$A$ point source of electromagnetic radiation has an average power output of $800 \ W$. Find the maximum value of the magnetic field at a distance of $3.5 \ m$ from the source.

$A$ plane electromagnetic wave travelling along the $X$-direction has a wavelength of $3 \ mm$. The variation in the electric field occurs in the $Y$-direction with an amplitude of $66 \ Vm^{-1}$. The equations for the electric and magnetic fields as a function of $x$ and $t$ are respectively:

The correct statement among the following is:

Identify the correct statements from the following descriptions of various properties of electromagnetic waves.
$A$. In a plane electromagnetic wave,the electric field and magnetic field must be perpendicular to each other,and the direction of propagation of the wave should be along the electric field or magnetic field.
$B$. The energy in an electromagnetic wave is divided equally between the electric and magnetic fields.
$C$. Both the electric field and magnetic field are parallel to each other and perpendicular to the direction of propagation of the wave.
$D$. The electric field,magnetic field,and direction of propagation of the wave must be mutually perpendicular to each other.
$E$. The ratio of the amplitude of the magnetic field $(B_0)$ to the amplitude of the electric field $(E_0)$ is equal to the reciprocal of the speed of light $(1/c)$.
Choose the most appropriate answer from the options given below:

The peak value of the magnetic field of an electromagnetic wave moving in a magnetic field is $20 \, nT$. The peak value of the electric field intensity is ..... $V/m$.

The mean intensity of radiation on the surface of the Sun is about $10^{8} \ W/m^2$. The $rms$ value of the corresponding magnetic field is closest to