The magnetic field in a plane electromagnetic wave is given by:
\(B_y = 2\times10^{-7} \text{sin}\left(\pi \times10^{3}x+3\pi\times10^{11}t\right )T\)${}_{}$
The wavelength is:
1. \(\pi\times 10^{3}~\text{m}\)
2. \(2\times10^{-3}~\text{m}\)
3. \(2\times10^{3}~\text{m}\)
4. \(\pi\times 10^{-3}~\text{m}\)

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

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

(a) The wavelength λ is 188.4 m
(b) The wave number k is 0.33 rad / m
(c) The wave amplitude is 10 V / m
(d) The wave is propagating along + x direction

Which one of the following pairs of statements is correct?

1. (a) and (b)

2. (b) and (c)

3. (c) and (d)

4. (a) and (c)

The EM wave with the shortest wavelength among the following is:

The frequency order for \(\gamma\) - rays (\(b\)), X – rays (\(a\)), and UV – rays (\(c\)) is:

If \(\lambda_{\mathrm{v}}, \lambda_{\mathrm{x}},\) and\(\lambda_\mathrm{m}\) represent the wavelengths of visible light, x-rays and microwaves respectively, then:
1. \( \lambda_{\mathrm{m}}>\lambda_{\mathrm{x}}>\lambda_{\mathrm{v}} \)
2. \( \lambda_\mathrm{v}>\lambda_\mathrm{m}>\lambda_\mathrm{x } \)
3. \( \lambda_\mathrm{v}>\lambda_\mathrm{x}>\lambda_\mathrm{m }\)
4. \(\lambda_{\mathrm{m}}>\lambda_{\mathrm{v}}>\lambda_{\mathrm{x}}\)

Which of the following has the minimum wavelength?
1. X-rays
2. Ultraviolet rays
3. γ-rays
4. Cosmic rays

What is the cause of “Greenhouse effect”?

1. Infra-red rays

2. Ultraviolet rays

3. X-rays

4. Radio waves

If the frequency of an E.M. wave is 10 MHz, then its wavelength is:
1.  30 m
2.  300 m
3.  3 m
4.  none of the above

The velocity of electromagnetic waves is parallel to:

1. $\overrightarrow{\mathrm{B}}\times \overrightarrow{\mathrm{E}}$

2. $\overrightarrow{\mathrm{E}}\times \overrightarrow{\mathrm{B}}$

3. $\overrightarrow{\mathrm{E}}$

4. $\overrightarrow{\mathrm{B}}$