For an $EM$ wave,the electric field intensity due to a bulb of $100\ W$ at a distance of $3\ m$ is $E$. What is the electric field intensity produced by radiations coming from a $50\ W$ bulb at the same distance?

If the relative permeability and dielectric constant of a medium are $\mu_r$ and $K$ respectively,then the refractive index $n$ of the medium is:

Long-distance radio broadcasting uses which of the following waves?

$A$ mathematical representation of an 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 $I$ in terms of $E_{max}$ and universal constants $\mu_0, \epsilon_0$?

In an electromagnetic wave,if $\overrightarrow{E}$ is the electric field and $\overrightarrow{B}$ is the magnetic field,then the direction of propagation of the wave is given by:

An electromagnetic wave with frequency $\omega$ and wavelength $\lambda$ travels in the $+y$ direction. Its magnetic field is along the $+x$ axis. The vector equation for the associated electric field (of amplitude $E_0$) is: