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

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

Which of the following has the minimum wavelength?
1. \(X\text-\)rays
2. Ultraviolet rays
3. \(\gamma\text-\)rays
4. Cosmic rays

What is the cause of “Greenhouse effect”?
1. Infra-red rays
2. Ultraviolet rays
3. \(X\text-\)rays
4. Radio waves

If the frequency of an EM 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. $\overrightarrow{\mathrm{B}}$