Suppose that the electric field of an electromagnetic wave in vacuum is $E = (3.1 \text{ NC}^{-1}) \cos [(1.8 \text{ rad m}^{-1}) y + (5.4 \times 10^6 \text{ rad s}^{-1}) t] \hat{i}$. What is the wavelength $\lambda$ (in $\text{ m}$)?

An $EM$ wave from air enters a medium. The electric fields are $\overrightarrow {{E_1}} = {E_{01}}\hat x\cos[2\pi v(\frac{z}{c} - t)]$ in air and $\overrightarrow {{E_2}} = {E_{02}}\hat x\cos[k(2z - ct)]$ in medium,where the wave number $k$ and frequency $v$ refer to their values in air. The medium is nonmagnetic. If $\varepsilon_{r_1}$ and $\varepsilon_{r_2}$ refer to relative permittivities of air and medium respectively,which of the following options is correct?

The solar radiation is:

When an electromagnetic wave passes through a dielectric medium,the transmitted wave has:

The rms value of the electric field of an electromagnetic wave emitted by a source is $660 \ NC^{-1}$. The average energy density of the electromagnetic wave is

The peak electric field produced by the radiation coming from the $80\, W$ bulb at a distance of $10\, m$ is $\frac{x}{10} \sqrt{\frac{\mu_{0} c }{\pi}} \,\frac{ V }{ m }$. The efficiency of the bulb is $10\, \%$ and it is a point source. The value of $x$ is ...... .