The ratio of the amplitude of the magnetic field to the amplitude of the electric field for an electromagnetic wave propagating in a vacuum is equal to

1.  The ratio of magnetic permeability to the electric susceptibility of vacuum.

2.  Unity.

3.  The speed of light in vacuum.

4.  Reciprocal of the speed of light in vacuum.

Out options, which one can be used to produce a electromagnetic wave?

1.  A particle.

2.  An accelerating charge.

3.  A charge moving at a constant velocity.

4.  A stationary charge.

In an electromagnetic wave in free space, the root means the square value of the electric field is ${\mathrm{E}}_{\mathrm{rms}}$ = 6 V/rn. The peak value of the magnetic field is

1.  2.83 x ${10}^{-8}$ T

2.  0.70 x ${10}^{-8}$ T

3.  4.23 x ${10}^{-8}$ T

4.  1.41 x ${10}^{-8}$ T

An em wave is propagating in a medium with a velocity $\overrightarrow{\mathrm{V}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>\mathrm{V}\hat{\mathrm{i}}$. The instantaneous oscillating electric field of the em wave is along the +y-axis. Then the direction of the oscillating magnetic field of the em wave will be along

1.  -y direction

2.  +z direction

3.  -z direction

4.  -x direction

the electric field associated with an E.M. wave in vacuum is given by $\overrightarrow{\mathrm{E}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>\hat{i}<mspace\; width="1em"></mspace>40<mspace\; width="1em"></mspace>\cos <mspace\; width="1em"></mspace>(kz<mspace\; width="1em"></mspace>-<mspace\; width="1em"></mspace>6<mspace\; width="1em"></mspace>\times <mspace\; width="1em"></mspace>{10}^{8}t)$, where e, z, and t are in $\mathrm{V}<mspace\; width="1em"></mspace>{\mathrm{m}}^{-1}$, m and s respectively. The value of wave vector k is

1.  2 ${\mathrm{m}}^{-1}$

2.  0.5 ${\mathrm{m}}^{-1}$

3.  6 ${\mathrm{m}}^{-1}$

4.  3 ${\mathrm{m}}^{-1}$

The decreasing order of wavelength Of infrared. microwave, ultraviolet and gamma rays is

1.  infrared, microwave, ultraviolet, gamma rays.

2.  microwave, infrared, ultraviolet, gamma rays.

3.  gamma rays, ultraviolet, infrared, microwaves.

4.  microwaves, gamma rays, infrared, ultraviolet.

The electric and the magnetic field, associated with an electromagnetic wave, propagating along +z-axis, can be represented by

1.  $\left[\overrightarrow{\mathrm{E}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>{\mathrm{E}}_0\hat{\mathrm{j}},<mspace\; width="1em"></mspace>\overrightarrow{\mathrm{B}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>{\mathrm{B}}_0\hat{\mathrm{k}}\right]$

2.  $\left[\overrightarrow{\mathrm{E}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>{\mathrm{E}}_0\hat{i},<mspace\; width="1em"></mspace>\overrightarrow{\mathrm{B}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>{\mathrm{B}}_0\hat{\mathrm{j}}\right]$

3.  $\left[\overrightarrow{\mathrm{E}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>{\mathrm{E}}_0\hat{\mathrm{k}},<mspace\; width="1em"></mspace>\overrightarrow{\mathrm{B}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>{\mathrm{B}}_0\hat{\mathrm{i}}\right]$

4.  $\left[\overrightarrow{\mathrm{E}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>{\mathrm{E}}_0\hat{\mathrm{j}},<mspace\; width="1em"></mspace>\overrightarrow{\mathrm{B}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>{\mathrm{B}}_0\hat{\mathrm{i}}\right]$

The electric field of an electromagnetic wave in free space is given by:

$\overrightarrow{E}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>10<mspace\; width="1em"></mspace>\cos ({10}^{7}t<mspace\; width="1em"></mspace>+<mspace\; width="1em"></mspace>kx)\hat{j}<mspace\; width="1em"></mspace>V{m}^{-1}$, where, t and x are in seconds and meters respectively. It can be inferred that

a. The wavelength $\lambda$ is 188.4 m.

b. The wavenumber k is 0.33 rad ${\mathrm{m}}^{-1}$.

c. The wave amplitude is 10 V ${\mathrm{m}}^{-1}$.

d. The wave is propagating along + x direction.

Which of the following pairs of statements is correct?

1.  a, and b

2.  b, and c

3.  a, and c

4.  c, and d

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

1.  These waves do not require any material medium for propagation.

2.  Both electric and magnetic field vectors attain the maxima and minima at the same place and same time.

3.  The energy in the electromagnetic waves is divided equally between electric and magnetic vectors.

4.  Both electric and magnetic fields are parallel to each other and perpendicular to the direction of propagation of the wave.

The electric field part of an electromagnetic wave in a medium is represented by $E_x<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>0;$

$E_y<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>2.5\frac{N}{C}\cos \left[\left(2\pi <mspace\; width="1em"></mspace>\times <mspace\; width="1em"></mspace>{10}^6\frac{rad}{s}\right)t<mspace\; width="1em"></mspace>-<mspace\; width="1em"></mspace>\left(\mathrm{\pi }<mspace\; width="1em"></mspace>\times <mspace\; width="1em"></mspace>{10}^{-2}\frac{\mathrm{rad}}{\mathrm{m}}\right)x\right];<mspace\; width="1em"></mspace>E_z<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>0$

The wave is

1.  moving along x-direction with frequency ${10}^6$ Hz and wavelength 100 m.
2.  moving along x-direction with frequency ${10}^6$ Hz and wavelength 200 m.
3.  moving along —x-direction with frequency ${10}^6$ Hz and wavelength 200 m.
4.  moving along y-direction with frequency 2$\mathrm{\pi }$ x ${10}^6$ Hz and wavelength 200 m.