Show that the radiation pressure exerted by an electromagnetic wave of intensity $I$ on a surface kept in vacuum is $I/c$.

What happens to the intensity of light from a bulb if the distance from the bulb is doubled?

As a laser beam travels across the length of a room, its intensity essentially remains constant. What geometrical characteristic of LASER beam is responsible for the constant intensity which is missing in the case of light from the bulb?

An infinitely long thin wire carrying a uniform linear static charge density $\lambda$ is placed along the $z$-axis. The wire is set into motion along its length with a uniform velocity $v=u{\hat{k}}_z$. Calculate the pointing vector $\mathrm{S}=\frac{1}{{\mathrm{\mu }}_{\mathrm{o}}}\left(\mathrm{E}\times \mathrm{B}\right)$.

A plane EM wave travelling along $z$ direction is described by $E=E_0\sin (kz-\omega t)\hat{i}$ and $B=B_0\sin (kz-\omega t)\hat{j}$. Show that

The average energy density of the wave is given by

$U_{aV}=\frac{1}{4}{\epsilon }_0{E}_0^2+\frac{1}{4}\frac{B_0^2}{{\mu }_0}$

A plane EM wave travelling along $z$ direction is described by $E=E_0\sin (kz-\omega t)\hat{i}$ and $B=B_0\sin (kz-\omega t)\hat{j}$. Show that

The time averaged intensity of the wave is given by 

$I_{aV}=\frac{1}{2}C{\epsilon }_0{E}_0^2$