Embibe Experts Solutions for Chapter: Electromagnetic Waves, Exercise 3: Exercise-3

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

Which of the following statement is false for the properties of electromagnetic waves?

The electric field of an electromagnetic wave in free space is given by $\overrightarrow{E}=10\cos \left({10}^{7}t+kx\right)\hat{\mathrm{j}}$ $\mathrm{V} {\mathrm{m}}^{-1},$ where $t$ and $x$ are in seconds and metres respectively. It can be inferred that

(i) the wavelength $\lambda$ is $188.4 \mathrm{m}.$

(ii) the wave number $k$ is $0.33 \mathrm{rad} {\mathrm{m}}^{-1}$

(iii) the wave amplitude is $10 \mathrm{V} {\mathrm{m}}^{-1}$

(iv) the wave is propagating along $+x$ direction

Which one of the following pairs of statements is correct?

In an electromagnetic wave in free space the root mean square value of the electric field is $E_{\mathrm{rms}}= 6 \raisebox{1ex}{$\mathrm{V}$}\!\left/ \!\raisebox{-1ex}{$\mathrm{m}$}\right.$. The peak value of the magnetic field is

The decreasing order of the wavelength of infrared, microwaves, ultraviolet  and gamma rays is:  

An electromagnetic wave in vacuum has the electric and magnetic field $\overrightarrow{E}$ and $\overrightarrow{B}$, which are always perpendicular to each other. The direction of polarization is given by $\overrightarrow{X}$ and that of wave propagation by $\overrightarrow{k}$. Then

During the propagation of electromagnetic waves in a medium

An EM wave from air enters a medium. The electric fields are ${\overrightarrow{E}}_1=E_{01}\hat{x}\cos \left[2\mathrm{\pi \nu }\left(\frac{z}{c}-t\right)\right]$ in air and ${\overrightarrow{E}}_2=E_{02}\hat{x}\cos \left[k\left(2z-ct\right)\right]$ in medium where the wave number $k$ and frequency $\nu$ refer to their values in air. The medium is non-magnetic. If ${\epsilon }_{r_1}$ and ${\epsilon }_{r_2}$ refer to relative permittivity of air and medium, respectively, which of the following options is correct?