An electromagnetic wave,going through vacuum,is described by $E = E_0 \sin(kx - \omega t)$. Which of the following is independent of wavelength?

Energy stored in electromagnetic oscillations is in the form of

$A$ sky wave with a frequency $55 \, MHz$ is incident on the $D$-region of the Earth's atmosphere at $45^\circ$. The angle of refraction is ......... $^\circ$ (electron density for the $D$-region is $400 \, \text{electrons}/cm^3$).

The electric field of a plane electromagnetic wave is given by: $E_y = 69 \sin[0.6 \times 10^3 x - 1.8 \times 10^{11} t] \text{ V/m}$. The expression for the magnetic field associated with this electromagnetic wave is . . . . . . $T$.

$A$ laser beam has intensity $2.1 \times 10^{15} \ W/m^2$. The amplitude of the magnetic field in the beam is approximately: (in $T$)

Electromagnetic waves are emitted from a point source. The output power of the source is $1500 \, W$. The maximum value of the electric field at a point $3 \, m$ away from the source is ........ $V \, m^{-1}$.