$A$ laser beam of pulse power $10^{12} \ W$ is focused on an object area of $10^{-4} \ cm^2$. The energy flux in $W/cm^2$ at the point of focus is:

If the electric field intensity of a uniform plane electromagnetic wave is given as $E = -301.6 \sin (kz - \omega t) \hat{a}_{x} + 452.4 \sin (kz - \omega t) \hat{a}_{y} \text{ V/m}$. Then,the magnetic intensity $H$ of this wave in $\text{A/m}$ will be (Given: Speed of light in vacuum $c = 3 \times 10^{8} \text{ m/s}$,permeability of vacuum $\mu_{0} = 4\pi \times 10^{-7} \text{ N/A}^{2}$)

$A$ plane electromagnetic wave travelling along the $X-$ direction has a wavelength of $3\, mm$. The variation in the electric field occurs in the $Y-$ direction with an amplitude of $66\, Vm^{-1}$. The equations for the electric and magnetic fields as a function of $x$ and $t$ are respectively:

$A$ beam of light travelling along the $X$-axis is described by the electric field $E_{y} = 900 \sin \omega(t - x/c)$. The ratio of the electric force to the magnetic force on a charge $q$ moving along the $Y$-axis with a speed of $3 \times 10^{7} \, m/s$ will be:
[Given: speed of light $c = 3 \times 10^{8} \, m/s$]

The electric field part of an electromagnetic wave in a medium is represented by $E_x=0, E_y=2.5 \frac{N}{C} \cos \left[ (2\pi \times 10^6 \frac{rad}{s})t - (\pi \times 10^{-2} \frac{rad}{m})x \right]$,and $E_z=0$. The wave is

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