Light is an electromagnetic wave. Its speed in vacuum is given by the expression

Even though an electric field $E$ exerts a force $qE$ on a charged particle, the electric field of an $EM$ wave does not contribute to the radiation pressure (but transfers energy). Explain.

If the direction of propagation of an electromagnetic wave is along the $z$-axis,then the directions of the electric field $(E)$ and magnetic field $(B)$ are:

$A$ point source of electromagnetic radiation has an average power output of $800\,W$. The maximum value of the electric field at a distance of $3.5\,m$ from the source will be.....$V/m$.

This question has Statement-$1$ and Statement-$2$. Of the four choices given after the statements,choose the one that best describes the two statements.
Statement-$1$: Out of radio waves and microwaves,the radio waves undergo more diffraction.
Statement-$2$: Radio waves have a greater frequency compared to microwaves.

$A$ plane $EM$ wave travelling along $z-$ direction is described by $\vec E = E_0 \sin(kz - \omega t)\hat i$ and $\vec B = B_0 \sin(kz - \omega t)\hat j$. Show that:
$(i)$ The average energy density of the wave is given by $U_{av} = \frac{1}{4} \epsilon_0 E_0^2 + \frac{1}{4} \frac{B_0^2}{\mu_0}$.
$(ii)$ The time-averaged intensity of the wave is given by $I_{av} = \frac{1}{2} c \epsilon_0 E_0^2$.