$A$ charged particle oscillates about its mean equilibrium position with a frequency of $10^{9} \,Hz$. The frequency of electromagnetic waves produced by the oscillator is . . . . . . .

The oscillating electric and magnetic vectors of an electromagnetic wave are oriented along

If a source is transmitting electromagnetic waves of frequency $8.196 \times 10^{6} \ Hz$,then the wavelength of the $EM$ waves transmitted from the source will be . . . . . . . (in $cm$)

Which of the following statements are true?
$A.$ Speed of light in vacuum is dependent on the direction of propagation.
$B.$ Speed of light in a medium is independent of the wavelength of light.
$C.$ The speed of light is independent of the motion of the source.
$D.$ The speed of light in a medium is independent of intensity.
Choose the correct answer from the options given below:

An electromagnetic wave travelling in a lossless dielectric medium having a dielectric constant $\epsilon_r = 9$, has the electric field, $E_x = E_0 \sin (kz - 2\pi \times 10^6 t) \text{ Vm}^{-1}$ where $E_0$ is the amplitude and $k$ is the wave vector. Among the following options, the incorrect choice is :

An electromagnetic wave of frequency $1 \times 10^{14} \,Hz$ is propagating along the $z$-axis. The amplitude of the electric field is $4 \,Vm^{-1}$. What is the energy density of the electric field? (Permittivity of free space $\varepsilon_0 = 8.8 \times 10^{-12} \,C^2 \,N^{-1} \,m^{-2}$)