The magnetic field of a plane electromagnetic wave is given by $B = (400 \ \mu T) \sin [ (4.0 \times 10^{15} \ s^{-1}) (t - \frac{x}{c}) ]$. The average energy density corresponding to the electric field is:

$A$ sky wave with a frequency of $55 \text{ MHz}$ is incident on the $D$-region of the ionosphere at an angle of $45^\circ$. What is the angle of refraction? (The electron density in the $D$-region is $400 \text{ electrons/cm}^3$).

$A$ plane electromagnetic wave of frequency $50 \ MHz$ travels in free space. If the average energy densities in the electric field and magnetic field are $K_{E}$ and $K_{B}$ respectively,then the correct option in the following is

$A$ microwave oven heats food containing water molecules very efficiently under which of the following conditions?

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

$A$ mathematical representation of an electromagnetic wave is given by the two equations $E = E_{max} \cos(kx - \omega t)$ and $B = B_{max} \cos(kx - \omega t)$,where $E_{max}$ is the amplitude of the electric field and $B_{max}$ is the amplitude of the magnetic field. What is the intensity $I$ in terms of $E_{max}$ and universal constants $\mu_0, \epsilon_0$?