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

(Take $\mu_{{r}}=1$ )

The electric field intensity produced by the radiation coming from a $100\, W$ bulb at a distance of $3\, m$ is $E$. The electric field intensity produced by the radiation coming from $60\, W$ at the same distance is $\sqrt{\frac{x}{5}} E$. Where the value of $x=……… .$

A plane electromagnetic wave in a non-magnetic dielectric medium is given by $\vec E\, = \,{\vec E_0}\,(4 \times {10^{ – 7}}\,x – 50t)$ with distance being in meter and time in seconds. The dielectric constant of the medium is

If the magnetic field in a plane electromagnetic wave is given by

$\overrightarrow{\mathrm{B}}=3 \times 10^{-8} \sin \left(1.6 \times 10^{3} \mathrm{x}+48 \times 10^{10} \mathrm{t}\right) \hat{\mathrm{j}}\; \mathrm{T}$

then what will be expression for electric field?

An electromagnetic wave, going through vacuum is described by $E = {E_0}\sin (kx – \omega \,t)$. Which of the following is independent of wavelength