If E and B represent electric and magnetic field vectors of the electromagnetic wave, the direction of propagation of the electromagnetic wave is along:

1. E

2. B

3. B x E

4. E x B

The ratio of contributions made by the electric field and magnetic field components to the intensity of an EM wave is:

1. c : 1

2. ${\mathrm{c}}^2$ : 1

3. 1 : 1

4. $\sqrt{\mathrm{c}}$ : 1

An EM wave radiates outwards from a dipole antenna, with ${\mathrm{E}}_0$, as the amplitude of its electric field vector. The electric field ${\mathrm{E}}_0$, which transports significant energy from the source falls off as:

1. \(\frac{1}{r^3}\)

2. \(\frac{1}{r^2}\)

3. \(\frac{1}{r}\)

4. remains constant

An electromagnetic wave travels in a vacuum along the z-direction: \(E=\left(E_1 \hat{i}+E_2 \hat{j}\right) \cos (k z-\omega t)\). Choose the correct options from the following.

(a) The associated magnetic field is given as: \(E=\frac{1}{c}\left(E_1 \hat{i}+E_2 \hat{j}\right) \cos (k z-\omega t)\)
(b) The associated magnetic field is given as: \(E=\frac{1}{c}\left(E_1 \hat{i}-E_2 \hat{j}\right) \cos (k z-\omega t)\)
(c) The given electromagnetic field is circularly polarised.
(d) The given electromagnetic wave is plane polarised.

1. (b, c)

2. (a, c)

3. (a, d)

4. (c, d)

A plane electromagnetic wave propagating along x-direction can have the following pairs of E and B.

(a) E_x, B_y
(b) E_y, B_z
(c) B_x, E_y
(d) E_z, B_y

1. (b, c)
2. (a, c)
3. (b, d)
4. (c, d)

The electric field intensity produced by the radiations coming from 100 W bulb at a 3 m distance is E. The electric field intensity produced by the radiations coming from 50 W bulb at the same distance is:

1. \(\frac{E}{2}\)

2. \(2E\)

3. \(\frac{E}{\sqrt2}\)

4. \(\sqrt2E\)

Light with an energy flux of \(20~\text{W/cm}^2\)${\mathrm{}}^{}$ falls on a non-reflecting surface at normal incidence. If the surface has an area of \(30~\text{cm}^2\)${\mathrm{}}^{}$, the momentum delivered (for complete absorption) during \(30\) minutes is:
1. \(36\times10^{-5}~\text{kg-m/s}\)
2. \(36\times10^{-4}~\text{kg-m/s}\)
3. \(108\times10^{4}~\text{kg-m/s}\)
4. \(1.08\times10^{7}~\text{kg-m/s}\)

A linearly polarised electromagnetic wave given as $\mathrm{E}={\mathrm{E}}_0 \hat{\mathrm{i}} \cos (\mathrm{kz}-\mathrm{\omega t})$ is incident normally on a perfectly reflecting infinite wall at z = a. Assuming that the material of the wall is optically inactive, the reflected wave will be given as:

1. ${\mathbf{E}}_{\mathbf{r}}=-{\mathrm{E}}_0\hat{\mathrm{i}}\cos \hspace{0.17em}(\mathrm{kz}-\mathrm{\omega t})$

2. ${\mathbf{E}}_{\mathbf{r}}={\mathrm{E}}_0\hat{\mathrm{i}}\cos (\mathrm{kz}+\mathrm{\omega t})$

3. ${\mathbf{E}}_{\mathbf{r}}=-{\mathrm{E}}_0\hat{\mathrm{i}}\cos (\mathrm{kz}+\mathrm{\omega t})$

4. ${\mathbf{E}}_{\mathbf{r}}={\mathrm{E}}_0\hat{\mathrm{i}}\sin (\mathrm{kz}-\mathrm{\omega t})$

One requires 11 eV of energy to dissociate a carbon monoxide molecule into carbon and oxygen atoms. The minimum frequency of the appropriate electromagnetic radiation to achieve the dissociation lies in

1. visible region
2. infrared region
3. ultraviolet region
4. microwave region