The relative permittivity of distilled water is $81$. The velocity of light in it will be $....\times 10^{7} \text{ m/s}$. (Given $\mu_{r} = 1$) (in $.33$)

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:

If a source is transmitting electromagnetic waves of frequency $8.2 \times 10^6 \ Hz$,then the wavelength of the electromagnetic waves transmitted from the source will be.....$m$.

If the electric field intensity of a uniform plane electromagnetic wave is given as $E = -301.6 \sin (kz - \omega t) \hat{a}_{x} + 452.4 \sin (kz - \omega t) \hat{a}_{y} \text{ V/m}$. Then,the magnetic intensity $H$ of this wave in $\text{A/m}$ will be (Given: Speed of light in vacuum $c = 3 \times 10^{8} \text{ m/s}$,permeability of vacuum $\mu_{0} = 4\pi \times 10^{-7} \text{ N/A}^{2}$)

Show that the radiation pressure exerted by an $EM$ wave of intensity $I$ on a surface kept in vacuum is $\frac{I}{c}$.

The velocity of an electromagnetic wave is parallel to: