The electric field of a plane electromagnetic wave propagating through a non-magnetic medium is given by $E = 20 \cos (2 \times 10^{10} t - 200 x) \, V/m$. The dielectric constant of the medium is equal to: (Take $\mu_r = 1$)

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 $\mu_{0} = 4\pi \times 10^{-7} \text{ N/A}^{2}$)

The mean intensity of radiation on the surface of the Sun is about $10^{8} \ W/m^2$. The $rms$ value of the corresponding magnetic field is closest to

The sun delivers $10^{3} \,W m^{-2}$ of electromagnetic flux on the Earth's surface. The total power that is incident on a roof of dimensions $6 \,m \times 30 \,m$ is . . . . . . .

An electromagnetic wave of frequency $3 \, GHz$ enters a dielectric medium of relative electric permittivity $2.25$ from vacuum. The wavelength of this wave in that medium will be $....... \times 10^{-2} \, cm$.

The biological importance of the ozone layer is that: