A point source of $100\,W$ emits light with $5 \%$ efficiency. At a distance of $5\,m$ from the source, the intensity produced by the electric field component is :

A metal sample carrying a current along $X-$ axis with density $J_x$ is subjected to a magnetic field $B_z$ ( along $z-$ axis ). The electric field $E_y$ developed along $Y-$ axis is directly proportional io $J_x$ as well as $B_z$ . The constant of proportionality has $SI\, unit$.

A mathematical representation of electromagnetic wave is given by the two equations $E = E_{max}\,\, cos (kx -\omega\,t)$ and $B = B_{max} cos\, (kx -\omega\,t),$ where $E_{max}$ is the amplitude of the electric field and $B_{max}$ is the amplitude of the magnetic field. What is the intensity in terms of $E_{max}$ and universal constants $μ_0, \in_0.$

Energy stored in electromagnetic oscillations is in the form of

If an electromagnetic wave propagating through vacuum is described by $E_y=E_0 \sin (k x-\omega t)$; $B_z=B_0 \sin (k x-\omega t)$, then

The electric field component of a monochromatic radiation is given by

$\vec E = 2{E_0}\,\hat i\,\cos\, kz\,\cos\, \omega t$

Its magnetic field $\vec B$ is then given by