The magnetic field of a plane electromagnetic wave is given by $\vec B = B_0 \hat i \cos(kz - \omega t) + B_1 \hat j \cos(kz - \omega t)$,where $B_0 = 3 \times 10^{-5} \, T$ and $B_1 = 2 \times 10^{-6} \, T$. The rms value of the force experienced by a stationary charge $Q = 10^{-4} \, C$ at $z = 0$ is closest to:

The ratio of the average electric energy density to the total average energy density of an electromagnetic wave is:

The speed of an electromagnetic wave in a vacuum depends upon the source of radiation.

$A$ cube of unit volume contains $35 \times 10^7$ photons of frequency $10^{15} \text{ Hz}$. If the energy of all the photons is viewed as the average energy being contained in the electromagnetic waves within the same volume,then the amplitude of the magnetic field is $\alpha \times 10^{-9} \text{ T}$. Taking permeability of free space $\mu_0 = 4\pi \times 10^{-7} \text{ Tm/A}$,Planck's constant $h = 6 \times 10^{-34} \text{ Js}$ and $\pi = \frac{22}{7}$,the value of $\alpha$ is $.....$

When $\mu_r$ and $\epsilon_r$ are the relative permeability and relative permittivity (dielectric constant) respectively,the refractive index is given by:

In an electromagnetic wave,the electric field intensity is $100 \ Vm^{-1}$ and the magnetic intensity is $H_0 = 0.265 \ Am^{-1}$. The maximum intensity of radiation is ..... $Wm^{-2}$.