Q. No.The electric field associated with an electromagnetic wave in vacuum is given by \(E=40 \cos \left(k z-6 \times 10^8 t\right)\), where \(E\), \(z\), and \(t\) are in volt/m, meter, and second respectively.
The value of the wave vector \(k\) would be:
1. \(2~\text{m}^{-1}\)
2. \(0.5~\text{m}^{-1}\)
3. \(6~\text{m}^{-1}\)
4. \(3~\text{m}^{-1}\)
| 1. | The wavelength \(\lambda\) is \(188.4~\text{m}\). |
| 2. | The wave number \(k\) is \(0.33~\text{rad/m}.\) |
| 3. | The wave amplitude is \(10~\text{V/m}\). |
| 4. | The wave is propagating along \(+x\) direction |
Which one of the following pairs of statements is correct?
1. (3) and (4)
2. (1) and (2)
3. (2) and (3)
4. (1) and (3)
The electric and magnetic fields of an electromagnetic wave are:
| 1. | In phase and parallel to each other |
| 2. | In opposite phases and perpendicular to each other |
| 3. | In opposite phases and parallel to each other |
| 4. | In phase and perpendicular to each other |
In electromagnetic wave the phase difference between electric and magnetic field vectors \(\vec E~\text{and}~\vec B\) is:
1. \(0\)
2. \(\frac{\pi}{2}\)
3. \(\pi\)
4. \(\frac{\pi}{4}\)
An electromagnetic wave going through the vacuum is described by
Which is the following is/are independent of the wavelength?
| 1. | \(k\) | 2. | \(k \over \omega\) |
| 3. | \(k \omega\) | 4. | \( \omega\) |
Which of the following statements is false regarding the properties of electromagnetic waves?
| 1. | Both electric and magnetic field vectors attain the maxima and minima at the same place and the same time |
| 2. | The energy in an electromagnetic wave is divided equally between electric and magnetic vectors |
| 3. | Both electric and magnetic field vectors are parallel to each other and perpendicular to the direction of propagation of the wave |
| 4. | These waves do not require any material medium for propagation |
\(E_x=0;\)
\(E_{y} =\left(2.5\frac{\text{N}}{\text{C}}\right)\cos \left[\left(2 \pi \times 10^{6} \frac{\text{rad}}{\text{s}}\right) t- \left(\pi \times 10^{- 2} \frac{\text{rad}}{\text{m}}\right) x\right];\)
\(E_z= 0.\)
The wave is:
| 1. | Moving along \(y\text-\)direction with frequency \(2\pi\times 10^6~\text{Hz}\) and wavelength \(200\) m. |
| 2. | Moving along \(+x\text-\)direction with frequency \(10^6~\text{Hz}\) and wavelength \(100\) m. |
| 3. | Moving along \(+x\text-\)direction with frequency \(10^6~\text{Hz}\) and wavelength \(200\) m. |
| 4. | Moving along \(-x\text-\)direction with frequency \(10^6~\text{Hz}\) and wavelength \(200\) nm. |
In an electromagnetic wave:
| 1. | power is transmitted along the magnetic field. |
| 2. | power is transmitted along the electric field. |
| 3. | power is equally transferred along with the electric and magnetic fields. |
| 4. | power is transmitted in a direction perpendicular to both the fields. |
The electric field part of an electromagnetic wave in a vacuum is;
\(\vec{E}=(3.1~\text{N/C}) \cos \left[(1.8~\text{rad/m}) y+\left(5.4 \times 10^8 ~\text{rad/s}\right)t\right] \hat{i}.\) What is the frequency of the wave?
1. \(5.7\times 10^{7}~\text{Hz}\)
2. \(9.3\times 10^{7}~\text{Hz}\)
3. \(8.6\times 10^{7}~\text{Hz}\)
4. \(7.5\times 10^{7}~\text{Hz}\)
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. \(\pi\times 10^{-3}~\text{m}\)
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